Miscellaneous improvements to the nested groups feature

See merge request !8308

* Simplify code around group parent access check
* Rename 'Nested groups' to 'Subgroups' tab at group#show page
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Grapify the settings API

See merge request !8336

Set default sort for tags to Last updated and fix nav controls spacing

Closes #25925

See merge request !8263

CTRL+Enter does not submit a new merge request

Closes #26134

See merge request !8360

Revert MattermostNotificationService and SlackNotificationService to MattermostS…

Closes #25889

See merge request !8240

Fix RoutingError at ./spec/features/milestones/milestones_spec.rb

See merge request !8361

About GitLab link in sidebar that links to help page

Closes #24479

See merge request !8316

Check if user can read project before being assigned to issue

Closes #22664

See merge request !7980

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fix unclear closing issue behaviour on Merge Request show page

Closes #26152

See merge request !8345

Inherit permissions from parent group

See merge request !8071

fix left border in session tabs

Closes #24941

See merge request !8346

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Merge branch '24820-buttons-in-the-branches-page-are-stacking-on-top-of-each-other-depending-on-the-selected-filter' into 'master'

Resolve "Buttons in the "Branches" page are stacking on top of each other depending on the selected filter"

Closes #24820

See merge request !8074

Fix instances where clicking a comment anchor twice will scroll to the wrong position

Closes #24876

See merge request !8046

Fix GFM dropdown not showing at beginning of new lines

Closes #26145

See merge request !8338

Refactor line length css

Closes #26153

See merge request !8354

Fix spacing between nav control elements
Wrap navigation text on Tags list page

Defer tooltip update on Resolve Comment button after DOM cycle

Closes #25957

See merge request !8335

Change status colors of runners to better defaults

Closes #25430

See merge request !8334

Replace link to Resolve conflicts with buttons

Closes #21135

See merge request !8229

Ensure javascript classes declared outside an IIFE are properties of window

See merge request !8080

adds kaminari_pagination controller concern with bounded pagination to not displ…

Closes #19988

See merge request !8172

darkened hr border color in descriptions because of update of bootstrap

See merge request !8333

Parameter already enforced via grape

See merge request !8344