Merge branch 'merge-request-sha-info' into 'master'

Merge request sha info

## What does this MR do?

Exposes `sha` and `merge_commit_sha` items in `MergeRequest` API endpoint data.

## Are there points in the code the reviewer needs to double check?

No.

## Why was this MR needed?

It's useful information.

## What are the relevant issue numbers?

Closes #20456.

## Screenshots (if relevant)

N/A

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5966

1 files changed, 22 insertions, 2 deletions

diff --git a/doc/api/merge_requests.md b/doc/api/merge_requests.md
index f4760ceac7c..494040a1ce8 100644
--- a/doc/api/merge_requests.md
+++ b/doc/api/merge_requests.md
@@ -68,6 +68,8 @@ Parameters:
     "merge_when_build_succeeds": true,
     "merge_status": "can_be_merged",
     "subscribed" : false,
+    "sha": "8888888888888888888888888888888888888888",
+    "merge_commit_sha": null,
     "user_notes_count": 1,
     "should_remove_source_branch": true,
     "force_remove_source_branch": false,
@@ -135,6 +137,8 @@ Parameters:
   "merge_when_build_succeeds": true,
   "merge_status": "can_be_merged",
   "subscribed" : true,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": "9999999999999999999999999999999999999999",
   "user_notes_count": 1,
   "should_remove_source_branch": true,
   "force_remove_source_branch": false,
@@ -238,6 +242,8 @@ Parameters:
   "merge_when_build_succeeds": true,
   "merge_status": "can_be_merged",
   "subscribed" : true,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": null,
   "user_notes_count": 1,
   "should_remove_source_branch": true,
   "force_remove_source_branch": false,
@@ -322,6 +328,8 @@ Parameters:
   "merge_when_build_succeeds": true,
   "merge_status": "can_be_merged",
   "subscribed" : true,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": null,
   "user_notes_count": 0,
   "should_remove_source_branch": true,
   "force_remove_source_branch": false,
@@ -397,6 +405,8 @@ Parameters:
   "merge_when_build_succeeds": true,
   "merge_status": "can_be_merged",
   "subscribed" : true,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": null,
   "user_notes_count": 1,
   "should_remove_source_branch": true,
   "force_remove_source_branch": false,
@@ -499,6 +509,8 @@ Parameters:
   "merge_when_build_succeeds": true,
   "merge_status": "can_be_merged",
   "subscribed" : true,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": "9999999999999999999999999999999999999999",
   "user_notes_count": 1,
   "should_remove_source_branch": true,
   "force_remove_source_branch": false,
@@ -569,6 +581,8 @@ Parameters:
   "merge_when_build_succeeds": true,
   "merge_status": "can_be_merged",
   "subscribed" : true,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": null,
   "user_notes_count": 1,
   "should_remove_source_branch": true,
   "force_remove_source_branch": false,
@@ -724,7 +738,9 @@ Example response:
   },
   "merge_when_build_succeeds": false,
   "merge_status": "cannot_be_merged",
-  "subscribed": true
+  "subscribed": true,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": null
 }
 ```
 
@@ -798,7 +814,9 @@ Example response:
   },
   "merge_when_build_succeeds": false,
   "merge_status": "cannot_be_merged",
-  "subscribed": false
+  "subscribed": false,
+  "sha": "8888888888888888888888888888888888888888",
+  "merge_commit_sha": null
 }
 ```
 
@@ -891,6 +909,8 @@ Example response:
     "merge_when_build_succeeds": false,
     "merge_status": "unchecked",
     "subscribed": true,
+    "sha": "8888888888888888888888888888888888888888",
+    "merge_commit_sha": null,
     "user_notes_count": 7,
     "should_remove_source_branch": true,
     "force_remove_source_branch": false,