Fix expandable diffs ## What does this MR do? Fix expandable diffs and the master build. ## Are there points in the code the reviewer needs to double check? Nope. ## Why was this MR needed? https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4776#note_13003494 Doesn't need a CHANGELOG entry etc. See merge request !5200
Add rule about adding new header tab to the ui guide To address cases like https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3749#note_12994215 See merge request !5188
Update the health_check gem to the latest release ## What does this MR do? Update the health_check gem to the latest release, which allows us to drop some of our code for overwriting the email check ## Does this MR meet the acceptance criteria? - [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added - [ ] ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~ - [ ] ~~API support added~~ - Tests - [ ] ~~Added for this feature/bug~~ - [ ] All builds are passing - [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides) - [ ] Branch has no merge conflicts with `master` (if you do - rebase it please) - [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits) See merge request !5186
api: expose {should,force}_remove_source_branch
## What does this MR do?
Exposes the `should_remove_source_branch` and `force_remove_source_branch` booleans via the API.
## Are there points in the code the reviewer needs to double check?
I don't think so.
## Why was this MR needed?
See the commit message.
## What are the relevant issue numbers?
N/A
## 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
- [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] 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 !5184
Display tooltip for "Copy to Clipboard" button ## What does this MR do? Add a tooltip to the "Copy to Clipboard" button. ## Are there points in the code the reviewer needs to double check? Nope. ## Why was this MR needed? There was no tooltip. ## What are the relevant issue numbers? fixes #19640, #19682 ## Screenshots (wrong cursor is the fault of my screenshot program)  See merge request !5164
Make "Get started with Builds" Help Page link work properly
`help_page_path('ci/quick_start', 'README')` causes a link to `https://gitlab.com/help/ci%2Fquick_start/README` which in turn breaks every relative link on the page. This remedies the problem.
That said, this is probably a horrible way of fixing this issue, *but* it does work. I can’t find much information on linking this deeply with Rails routes.
If anyone has suggestions as to a better way of handling this, I'll gladly take them. I tried a few different things, but none of them really worked.
Resolves #14872.
cc: @axil @rspeicher @elstamey
See merge request !3561
Optimize cross ref system notes check ## What does this MR do? This MR optimizes system note visibility checking by memoizing the visible reference count, reducing the overhead of calling `Note#cross_reference_not_visible_for?`. ## Are there points in the code the reviewer needs to double check? Note that since a cross reference message contains, "Mentioned in XYZ", we EXPECT that there is at least one reference. That's why using the ref count > 0 works. ## Why was this MR needed? The previous implementation relied on `Note#cross_reference_not_visible_for?`, which essentially tries to render all the Markdown references in a system note and only displays the note if the user can see the referring project. But this duplicated the work that Banzai::NotesRenderer was doing already. This shaves about 0.8 s from the load time from https://gitlab.com/gitlab-com/operations/issues/42. ## What are the relevant issue numbers? #19273 ## Screenshots (if relevant) ## Does this MR meet the acceptance criteria? - [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added - [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md) - [ ] 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 !5070