Fixed pipeline action tooltips being cut off

Closes #29314

See merge request !9960

Adds pipeline mini-graph to system information box in Commit View

Closes #28494

See merge request !9902

Fix reply by email by fixing config/mail_room.yml to be interpretable without ActiveSupport

See merge request !9979

Moved the gear settings dropdown in the group view to a tab

Closes #23304

See merge request !9882

Revert the AddNotifiedOfOwnActivityToUsers migration

See merge request !9973

Revert "Merge branch 'option-to-be-notified-of-own-activity' into 'master'

See merge request !9974

Add missing steps of Pages source installation

Closes #29372

[ci skip]

See merge request !9923

Add quick submit for snippet forms

Closes #27534

See merge request !9911

This reverts commit 5e966688, reversing
changes made to b35378a9.

Better priority sorting

Closes #28754

See merge request !9938

Revert "Merge branch 'google-protobuf-3.2.0.1' into 'master'"

See merge request !9971

prevent filtering Issues by multiple milestones, authors, or assignees

Closes #27174

See merge request !9406

Copy code as GFM from diffs, blobs and GFM code blocks

See merge request !9874

don't show scrollbar on search field unless necessary

See merge request !9880

This reverts merge request !9932

to the first option inside said subtab.

Also code cleanup

Include time tracking attributes in webhooks payload

Closes #27271

See merge request !9942

Remove whitespace in group links

Closes #29449

See merge request !9947

Allow resolving conflicts with non-ASCII chars

Closes #26214

See merge request !9937

Add nested groups documentation

Closes #28761

See merge request !9783

We wanted to check that the text could be encoded as JSON, because
conflict resolutions are passed back and forth in that format, so the
file itself must be UTF-8. However, all strings from the repository come
back without an encoding from Rugged, making them ASCII_8BIT.

We force to UTF-8, and reject if it's invalid. This still leaves the
problem of a file that 'looks like' UTF-8 (contains valid UTF-8 byte
sequences), but isn't. However:

1. If the conflicts contain the problem bytes, the user will see that
   the file isn't displayed correctly.
2. If the problem bytes are outside of the conflict area, then we will
   write back the same bytes when we resolve the conflicts, even though
   we though the encoding was UTF-8.