Fix PlantUML integration in GFM

Closes #30557

See merge request !10651

Use constants in Gitlab::MarkupHelper

See merge request !10741

Refactor changing files in web UI

Closes #28711

See merge request !9323

Add retries to system hook worker

Closes #31109

See merge request !10801

Don't delete a branch involved in an open merge request in "Delete all merged branches" service

Closes #29427

See merge request !10727

The default number of Sidekiq retries is 25 over about 21 days.
If an external system is unavailable for a length of time, hooks
can pile up in the Sidekiq queues. If the situation gets bad enough
the retry jobs dropping back into the main queue can slow down
other jobs. Limit the retries to a sane number to avoid this
scenario.

Resolve "start discussion toggle clicking divider causes UI break"

Closes #30951

See merge request !10715

Add unique index to system note metadata

See merge request !10774

Implement search by extern_uid in Users API

See merge request !10509

Add renderNote animation and added spec

Closes #29977

See merge request !10623

Set the issuable sidebar to remain collapsed on mobile devices

Closes #28086

See merge request !10323

Fixed branches sort toggle being empty

Closes #30950

See merge request !10764

Removed target blank from the environments component

Closes #31029

See merge request !10726

Update groups.md found typo

See merge request !10792

Fixed group milestones date pickers not working

Closes #31095

See merge request !10779

Added profile name to user dropdown

Closes #30484

See merge request !10469

Merge branch '29734-prometheus-monitoring-page-displays-button-to-control-manual-actions' into 'master'

Remove manual deployment controls from Environment metrics page

Closes #29734

See merge request !10769

Remove node modules cache because we already use artifacts

Closes #29226 and #31137

See merge request !10781

Fixed project & group icons not being clickable

Closes #31073

See merge request !10778

Fixes #30557
Use "lang" attribute instead of "class" in PlantumlFilter.

Display issuable state only in notes and issuable description

Closes #30964

See merge request !10789

Destroy tooltip in async buttons and dropdowns

Closes #30985

See merge request !10768

Added and updated droplab docs

See merge request !10569

Customers were surprised by the previous behavior, which destroyed branches
even though an open merge request existed for it.

Closes #29427

Usage ping port

Closes #27750

See merge request !10481

Closes #30964

* master:
  Remove special naming of pipelines folder
  remove changelog (not needed)
  Fix active user count
  add spec and changelog
  Add migration to remove orphaned notification settings
  Improve container registry repository path specs
  Fix duplicated container repository names
  update textarea height and refocus when attaching files
  Remove IIFEs in filtered_search_bundle.js
  Remove IIFEs from diff_notes_bundle.js