Update guidance on handling shared secrets in HA setup

See merge request !1152

Snippet spam EE

See merge request !1148

Apply the same spam checks to public snippets (either personal snippets
that are public, or public snippets on public projects) as to issues on
public projects.

When a snippet is submitted, but there's an error, we didn't keep the
visibility level. As the default is private, this means that submitting
a public snippet that failed would then fall back to being a private
snippet.

Resolve ""Merge when pipeline succeeds" visible if approvals are pending"

Closes #1595

See merge request !1101

Add info on using both push/pull repository mirroring

See merge request !1146

[ci skip]

Update the 8.16.3 changelog in master

See merge request !1145

Ignore encrypted attributes in Import/Export (EE version)

See merge request !1140

Closes #24458

See merge request !8739
# Conflicts:
#	spec/features/projects/import_export/test_project_export.tar.gz

CE upstream

See merge request !1139

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

UX Guide: minor updates

See merge request !8862

[ci skip] UX guide: clean up term tables in copy

[ci skip] UX guide: update dropdown max height for multiline items

Remove hard-coded absolute URLs from all frontend assets

See merge request !8831

Fixed Issuable sidebar so it remains closed on mobile/smaller screen devices

See merge request !7466

[ci skip]

[ci skip]

Merge branch '27248-filtered-search-does-not-allow-filtering-labels-with-multiple-words' into 'master'

Fix filtering label and milestone with multiple words

Closes #27248 and #27334

See merge request !8830

[EE] Resolve "NameError: uninitialized constant ApplicationSetting::DEFAULTS"

See merge request !1124

Resolve "NameError: uninitialized constant ApplicationSetting::DEFAULTS"

Closes #27280

See merge request !8805