Merge remote-tracking branch 'upstream/master' into 27377-preload-pipeline-entity27377-preload-pipeline-entity

* upstream/master: (2534 commits)
  Update VERSION to 9.3.0-pre
  Update CHANGELOG.md for 9.2.0
  removes unnecessary redundacy in usage ping doc
  Respect the typo as rubocop said
  Add a test to ensure this works on MySQL
  Change pipelines schedules help page path
  change domain to hostname in usage ping doc
  Fixes broken MySQL migration for retried
  Show password field mask while editing service settings
  Add notes for supported schedulers and cloud providers
  Move environment monitoring to environments doc
  Add docs for change of Cache/Artifact restore order"
  Avoid resource intensive login checks if password is not provided
  Change translation for 'coding' by 'desarrollo' for Spanish
  Add to docs: issues multiple assignees
  rename "Add emoji" and "Award emoji" to "Add reaction" where appropriate
  Add project and group notification settings info
  32570 Fix border-bottom for project activity tab
  Add users endpoint to frontend API class
  Rename users on mysql
  ...

1 files changed, 31 insertions, 25 deletions

diff --git a/doc/api/merge_requests.md b/doc/api/merge_requests.md
index 2e0545da1c4..cb22b67f556 100644
--- a/doc/api/merge_requests.md
+++ b/doc/api/merge_requests.md
@@ -1,4 +1,4 @@
-# Merge requests
+# Merge requests API
 
 ## List merge requests
 
@@ -11,15 +11,21 @@ GET /projects/:id/merge_requests
 GET /projects/:id/merge_requests?state=opened
 GET /projects/:id/merge_requests?state=all
 GET /projects/:id/merge_requests?iids[]=42&iids[]=43
+GET /projects/:id/merge_requests?milestone=release
+GET /projects/:id/merge_requests?labels=bug,reproduced
 ```
 
 Parameters:
 
-- `id` (required) - The ID of a project
-- `iid` (optional) - Return the request having the given `iid`
-- `state` (optional) - Return `all` requests or just those that are `merged`, `opened` or `closed`
-- `order_by` (optional) - Return requests ordered by `created_at` or `updated_at` fields. Default is `created_at`
-- `sort` (optional) - Return requests sorted in `asc` or `desc` order. Default is `desc`
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `id` | integer | yes | The ID of a project |
+| `iids` | Array[integer] | no | Return the request having the given `iid` |
+| `state`   | string  | no    | Return all merge requests or just those that are `opened`, `closed`, or `merged`|
+| `order_by`| string  | no    | Return requests ordered by `created_at` or `updated_at` fields. Default is `created_at` |
+| `sort`    | string  | no    | Return requests sorted in `asc` or `desc` order. Default is `desc`  |
+| `milestone`  | string  | no | Return merge requests for a specific milestone |
+| `labels`  | string  | no | Return merge requests matching a comma separated list of labels |
 
 ```json
 [
@@ -87,7 +93,7 @@ GET /projects/:id/merge_requests/:merge_request_iid
 
 Parameters:
 
-- `id` (required) - The ID of a project
+- `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user
 - `merge_request_iid` (required) - The internal ID of the merge request
 
 ```json
@@ -155,7 +161,7 @@ GET /projects/:id/merge_requests/:merge_request_iid/commits
 
 Parameters:
 
-- `id` (required) - The ID of a project
+- `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user
 - `merge_request_iid` (required) - The internal ID of the merge request
 
 
@@ -192,7 +198,7 @@ GET /projects/:id/merge_requests/:merge_request_iid/changes
 
 Parameters:
 
-- `id` (required) - The ID of a project
+- `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user
 - `merge_request_iid` (required) - The internal ID of the merge request
 
 ```json
@@ -271,7 +277,7 @@ POST /projects/:id/merge_requests
 
 | Attribute              | Type    | Required | Description                                                                     |
 | ---------              | ----    | -------- | -----------                                                                     |
-| `id`                   | string  | yes      | The ID of a project                                                             |
+| `id`                   | integer/string  | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
 | `source_branch`        | string  | yes      | The source branch                                                               |
 | `target_branch`        | string  | yes      | The target branch                                                               |
 | `title`                | string  | yes      | Title of MR                                                                     |
@@ -347,7 +353,7 @@ PUT /projects/:id/merge_requests/:merge_request_iid
 
 | Attribute              | Type    | Required | Description                                                                     |
 | ---------              | ----    | -------- | -----------                                                                     |
-| `id`                   | string  | yes      | The ID of a project                                                             |
+| `id`                   | integer/string  | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
 | `merge_request_iid`    | integer | yes      | The ID of a merge request                                                       |
 | `target_branch`        | string  | no       | The target branch                                                               |
 | `title`                | string  | no       | Title of MR                                                                     |
@@ -422,9 +428,9 @@ Only for admins and project owners. Soft deletes the merge request in question.
 DELETE /projects/:id/merge_requests/:merge_request_iid
 ```
 
-| Attribute           | Type    | Required | Description                          |
-| ---------           | ----    | -------- | -----------                          |
-| `id`                | integer | yes      | The ID of a project                  |
+| Attribute | Type    | Required | Description                          |
+| --------- | ----    | -------- | -----------                          |
+| `id`      | integer/string  | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request |
 
 ```bash
@@ -450,7 +456,7 @@ PUT /projects/:id/merge_requests/:merge_request_iid/merge
 
 Parameters:
 
-- `id` (required)                           - The ID of a project
+- `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user
 - `merge_request_iid` (required)            - Internal ID of MR
 - `merge_commit_message` (optional)         - Custom merge commit message
 - `should_remove_source_branch` (optional)  - if `true` removes the source branch
@@ -524,7 +530,7 @@ PUT /projects/:id/merge_requests/:merge_request_iid/cancel_merge_when_pipeline_s
 ```
 Parameters:
 
-- `id` (required)                           - The ID of a project
+- `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user
 - `merge_request_iid` (required)            - Internal ID of MR
 
 ```json
@@ -596,7 +602,7 @@ GET /projects/:id/merge_requests/:merge_request_iid/closes_issues
 
 | Attribute           | Type    | Required | Description                          |
 | ---------           | ----    | -------- | -----------                          |
-| `id`                | integer | yes      | The ID of a project                  |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                  |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request |
 
 ```bash
@@ -671,7 +677,7 @@ POST /projects/:id/merge_requests/:merge_request_iid/subscribe
 
 | Attribute           | Type    | Required | Description                 |
 | ---------           | ----    | -------- | -----------                 |
-| `id`                | integer | yes      | The ID of a project         |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user         |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request |
 
 ```bash
@@ -745,7 +751,7 @@ POST /projects/:id/merge_requests/:merge_request_iid/unsubscribe
 
 | Attribute           | Type    | Required | Description                          |
 | ---------           | ----    | -------- | -----------                          |
-| `id`                | integer | yes      | The ID of a project                  |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                  |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request |
 
 ```bash
@@ -819,7 +825,7 @@ POST /projects/:id/merge_requests/:merge_request_iid/todo
 
 | Attribute           | Type    | Required | Description                          |
 | ---------           | ----    | -------- | -----------                          |
-| `id`                | integer | yes      | The ID of a project                  |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                  |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request |
 
 ```bash
@@ -1027,7 +1033,7 @@ POST /projects/:id/merge_requests/:merge_request_iid/time_estimate
 
 | Attribute           | Type    | Required | Description                              |
 | ---------           | ----    | -------- | -----------                              |
-| `id`                | integer | yes      | The ID of a project                      |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                      |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request     |
 | `duration`          | string  | yes      | The duration in human format. e.g: 3h30m |
 
@@ -1056,7 +1062,7 @@ POST /projects/:id/merge_requests/:merge_request_iid/reset_time_estimate
 
 | Attribute           | Type    | Required | Description                                  |
 | ---------           | ----    | -------- | -----------                                  |
-| `id`                | integer | yes      | The ID of a project                          |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                          |
 | `merge_request_iid` | integer | yes      | The internal ID of a project's merge_request |
 
 ```bash
@@ -1084,7 +1090,7 @@ POST /projects/:id/merge_requests/:merge_request_iid/add_spent_time
 
 | Attribute           | Type    | Required | Description                              |
 | ---------           | ----    | -------- | -----------                              |
-| `id`                | integer | yes      | The ID of a project                      |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                      |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request     |
 | `duration`          | string  | yes      | The duration in human format. e.g: 3h30m |
 
@@ -1113,7 +1119,7 @@ POST /projects/:id/merge_requests/:merge_request_iid/reset_spent_time
 
 | Attribute           | Type    | Required | Description                                  |
 | ---------           | ----    | -------- | -----------                                  |
-| `id`                | integer | yes      | The ID of a project                          |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                          |
 | `merge_request_iid` | integer | yes      | The internal ID of a project's merge_request |
 
 ```bash
@@ -1139,7 +1145,7 @@ GET /projects/:id/merge_requests/:merge_request_iid/time_stats
 
 | Attribute           | Type    | Required | Description                          |
 | ---------           | ----    | -------- | -----------                          |
-| `id`                | integer | yes      | The ID of a project                  |
+| `id`                | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user                  |
 | `merge_request_iid` | integer | yes      | The internal ID of the merge request |
 
 ```bash