Fix broken link in feature proposal template

See merge request gitlab-org/gitlab-ce!23957

Resolve "build-loader-animation dots misaligned"

Closes #52620

See merge request gitlab-org/gitlab-ce!23959

Add support for attaching epics to an epic

Closes #8333

See merge request gitlab-org/gitlab-ee!8637

Remove deprecated xhr from specs

Closes #55448

See merge request gitlab-org/gitlab-ce!23949

Remove &:not(.use-csslab) from table to fix dark diff themes

Closes #55282

See merge request gitlab-org/gitlab-ce!23941

Removes batch_review_notification feature flag

See merge request gitlab-org/gitlab-ee!8933

Fixed merge spec conflict

Closes #8939

See merge request gitlab-org/gitlab-ee!8934

- we now use the hierarchy class also for epics
- also rename supports_nested_groups? into supports_nested_objects?
  - move it to a concern
- add checks for epics

Integrates frontend with API to enable
attaching epics to an epic

Add controller + services for:
 - setting a parent
 - list epics
 - delete associarion

Adds backstage support to related issues app
to enable attaching epics to an epic

Remove epics field for projects not in groups

Closes #7866

See merge request gitlab-org/gitlab-ee!8919

Add missing entries to locale/gitlab.pot

Closes #8940

See merge request gitlab-org/gitlab-ee!8935

Also fixes epics field being shown in MRs

CE port: Rename GroupHierarchy into ObjectHierarchy

See merge request gitlab-org/gitlab-ce!23923

restores changes from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23816

Resolve "Add tests for "Redesign projects lists UI""

Closes #55359

See merge request gitlab-org/gitlab-ce!23915

Fix sidekiq-reliable-fetch version

Closes sidekiq-reliable-fetch#18

See merge request gitlab-org/gitlab-ce!23937

This feature flag was being used as a gatekeeper
for the one notification for every batch review
feature.

We no longer require the feature flag since the
code is working as expected

Removed pipeline_ci_sources_only feature flag

See merge request gitlab-org/gitlab-ce!23926

Upgrade @gitlab/ui to 1.16.2

See merge request gitlab-org/gitlab-ce!23946

Cache avatar URLs and paths within a request

Closes #55355

See merge request gitlab-org/gitlab-ce!23950

Resolve "Hide cluster features that don't work yet with Group Clusters"

Closes #55103

See merge request gitlab-org/gitlab-ce!23935

Merge branch '51606-expanding-a-diff-while-having-an-open-comment-form-will-always-scroll-down-to-the-comment' into 'master'

Resolve "Expanding a diff while having an open comment form will always scroll down to the comment"

Closes #51606

See merge request gitlab-org/gitlab-ce!23849