Fix 9.1 Gitaly source update steps

Closes #31288

See merge request !10877

Eliminate N+1 queries in loading namespaces for every issuable in milestones

See merge request !10871

Ensure replying to an individual note by email creates a note with its own discussion ID

Closes #31067

See merge request !10890

Fix email not being sent after project export

Closes #30676

See merge request !10578

[ci skip]

This reverts commit 0385b5b3.

discussions docs

See merge request !10390

Based on !10841 Fix Error 500 when referencing issue with project in pending delete

Closes #31215

See merge request !10843

Mention Microsoft teams service in project services doc

See merge request !10815

Add doc for scheduled trigger

Closes #30440

See merge request !10591

Port of 31189-pipelines-error-state to 9-1-stable

See merge request !10844

Fix user activities API version in docs

[ci skip]

See merge request !10822

Fix encoding issue exporting a project

Closes #31186

See merge request !10824

Replace builds_enabled with jobs_enabled in projects API v4

Closes #31012

See merge request !10786

Add Fork/Cancel confirmation to "Replace"/"Delete" buttons

Closes #30637

See merge request !10602

Update CI templates to include 9.1 templates

See merge request !10807

Update move icon to match others

Closes #31116

See merge request !10790

Milestones documentation refactor

See merge request !10812

Add email receiver metrics

See merge request !10814

Kubernetes service namespace

Closes #30445

See merge request !10821

Show sub-nav under Merge Requests when issue tracker is non-default

Closes #30779

See merge request !10658

Don't run the downtime check on stable branches, or tags/master

See merge request !10794

same fix on stable for issue title poll on load visibility check

See merge request !10820

Port of fix/29125-ee to CE

Closes #29125

See merge request !10796

Usage ping port

Closes #27750

See merge request !10481

Add documentation for inactive users in the User cohort

Closes #31195

See merge request !10809

Do not append issuable state to links with custom anchor

Closes #30916

See merge request !10782

Add unique index to system note metadata

See merge request !10774

Fixed group milestones date pickers not working

Closes #31095

See merge request !10779

Fixed branches sort toggle being empty

Closes #30950

See merge request !10764

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

Resolve "start discussion toggle clicking divider causes UI break"

Closes #30951

See merge request !10715

Fix PlantUML integration in GFM

Closes #30557

See merge request !10651