Standardize use of `content` parameter in snippets API

Closes #66673

See merge request gitlab-org/gitlab-ce!32296

Resolve "Issue due notification emails are threaded incorrectly"

See merge request gitlab-org/gitlab-ce!32325

Add E2E spec to ensure that issue closes with commit message

Closes gitlab-org/quality/testcases#15

See merge request gitlab-org/gitlab-ce!32347

Add E2E spec to test that issue closes with commit message

Set dast job to extend .review-only

Closes #66718

See merge request gitlab-org/gitlab-ce!32357

Update documentation screenshot

See merge request gitlab-org/gitlab-ce!32369

Fix capitalization in more docs

See merge request gitlab-org/gitlab-ce!32370

Fix capitalization in docs for works like GitLab, Git
Omnibus, etc

Make Auto DevOps requirements easier to read

See merge request gitlab-org/gitlab-ce!32246

Simplify internal post receive messages

Closes #59808

See merge request gitlab-org/gitlab-ce!31640

New project milestone primary button

See merge request gitlab-org/gitlab-ce!32355

This reverts commit af5242ecb682189c5d8276e1ab1ffe5ce844f2e5.

Remove checkbox styling

See merge request gitlab-org/gitlab-ce!31500

Resolve "Migrate spec/javascripts/vue_mr_widget/components/states/mr_widget_auto_merge_failed_spec.js to Jest"

See merge request gitlab-org/gitlab-ce!32282

Merge branch '56130-operations-environments-shows-incorrect-deployment-date-for-manual-deploy-jobs' into 'master'

Show correct deployment date for a manual job

Closes #56130

See merge request gitlab-org/gitlab-ce!32072

Mention Jest in testing guide docs

See merge request gitlab-org/gitlab-ce!32324

- Reword relationship between Jest/Karma/Jasmine
- Prefer inline URLs, per the [docs]

[docs]: https://docs.gitlab.com/ee/development/documentation/styleguide.html#links

Merge branch '62284-follow-up-from-resolve-api-to-get-all-project-group-members-returns-duplicates' into 'master'

Resolve "Follow-up from "Resolve "API to get all project/group members returns duplicates"""

Closes #62284

See merge request gitlab-org/gitlab-ce!28887

There was some confusion over whether `code` or `content` is the right
parameter for snippets. Internally, the database stores
`content`. However:

1. Project snippets use `code`. `code` gets remapped in `content` in
`lib/api/project_snippets.rb`.

2. Personal snippets use `content`.

To unify these APIs, allow an alias of `content` to work for project
snippets.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/66673

Update a few redirected links

Closes #64285

See merge request gitlab-org/gitlab-ce!32195

Add warnings to performance bar response

See merge request gitlab-org/gitlab-ce!31054

Add index to improve query performance

See merge request gitlab-org/gitlab-ce!31988

It should not be a start to a new thread but rather
a reply to an existing thread

Now we have cluster_id, state index, we don't the cluster_id index as
well.

For Environment.deployed_to_cluster

Resolve "Notes are persisted with the user's locale"

See merge request gitlab-org/gitlab-ce!32264

Instead of sending varied data to Gitaly, and making Gitaly construct
various messages, build the messages first and have Gitaly print
either basic messages or alert messages, in the order they come.

Depends on https://gitlab.com/gitlab-org/gitaly/merge_requests/1410

Commit to current branch by default in Web IDE E2E tests

See merge request gitlab-org/gitlab-ce!32248

Reduce the number of SQL requests on MR-show

See merge request gitlab-org/gitlab-ce!32192

- Extract MR fields for notes into a separate serializer
- Check if pipelines are empty via count

Resolve "Migrate spec/javascripts/vue_shared/components/file_icon_spec.js to Jest"

See merge request gitlab-org/gitlab-ce!32278

Save board lists collapsed setting

Closes #52758

See merge request gitlab-org/gitlab-ce!31069

Persists if a board list is collapsed for each user.

Fix top-nav search bar dropdown on xl displays

Closes #64120 and #66075

See merge request gitlab-org/gitlab-ce!31864