Fix race condition of `refs/merge` competing overwrite

Closes #12562

See merge request gitlab-org/gitlab-ee!14495

Reduce N+1 queries in MergeRequestsController#ci_environment_status

See merge request gitlab-org/gitlab-ce!30224

Upgrade prometheus-client-mmap to 0.9.7

See merge request gitlab-org/gitlab-ce!30430

Remove a high cardinality Prometheus metric

See merge request gitlab-org/gitlab-ce!30122

Add lint rule that headings must increment one level at a time

See merge request gitlab-org/gitlab-ce!30376

Also fixes instances in Markdown that broke the rule.

Starting a new discussion only on line without Draft note created on it

See merge request gitlab-org/gitlab-ce!30413

- fixed attribute to be not hyphenated
- applied parallel diffs view on CE
- separated left and right drafts
- added fallback for hasDrafts

Remove minimum required characters for fuzzy search if no trigram is used

See merge request gitlab-org/gitlab-ce!29810

Starting a new discussion only on line without Draft note created on it

Closes #12632

See merge request gitlab-org/gitlab-ee!14569

- fixed attribute to be hyphenated
- applied hasDraft to parallel view
- added fallback to hasDraft
- fixed type for draft to be parallel
- fixed parallel diff view
- added a changelog entry
- separated left and right drafts

As a workaround for https://gitlab.com/gitlab-org/gitlab-ce/issues/64116

Docs: Changing badges to use parentheses not brackets

See merge request gitlab-org/gitlab-ce!30439

Previously, we used brackets to denote the tier badges,
but this made Kramdown, the docs site Markdown renderer,
show many warnings when building the site. This is now
fixed by using parentheses instead of square brackets.

This was caused by [PREMIUM] looking like a link to
Kramdown, which couldn't find a URL there.

See:
- https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/484
- https://gitlab.com/gitlab-org/gitlab-ce/issues/63800

Replace runtime isEE check with compile time one

Closes #60213

See merge request gitlab-org/gitlab-ce!30351

Replace runtime isEE check with compile time one

See merge request gitlab-org/gitlab-ee!14570

Vue-i18n: autofix for app/assets/javascripts/vue_shared directory

See merge request gitlab-org/gitlab-ce!30287

i18n linting for .vue files under the
app/assets/javascripts/vue_shared directory

EE Port: Vue i18n js vue shared directory ee

See merge request gitlab-org/gitlab-ee!14544

i18n linting for .vue files under the
app/assets/javascripts/vue_shared directory

Vue-i18n: autofix for app/assets/javascripts/vue_merge_request_widget directory

See merge request gitlab-org/gitlab-ce!30035

i18n linting for .vue files under the
app/assets/javascripts/vue_merge_request_widget directory

Vue-i18n: app/assets/javascripts/vue_merge_request_widget directory

See merge request gitlab-org/gitlab-ee!14380

i18n linting for .vue files under the
app/assets/javascripts/vue_merge_request_widget directory

Update dependency @gitlab/svgs to ^1.67.0

See merge request gitlab-org/gitlab-ce!30402

Removes EE differences for app/views/admin/users/show.html.haml

Closes gitlab-ee#12533

See merge request gitlab-org/gitlab-ce!30407

Today, Pipelines for merge train run on `refs/merge`,
however, this causes a race condition that it can be
overwritten by CheckMergeabilityService.

This patch fixes the problem by generating `refs/train`
for those pipelines.

Extract BoardScope component

See merge request gitlab-org/gitlab-ee!14556

Resolve "Removing an image via Web IDE shows binary data"

Closes #60856

See merge request gitlab-org/gitlab-ce!30314