New `Api.projectMergeRequests` allows:
 - to query for all MRs on a project without specifying `mergeRequestId`
 - to filter the returned MRs using parameters from
 https://bit.ly/2H7We4V

 The new API request is used for fetching information about MRs
 associated with a particular branch in Web IDE to have IdeSidebar
 behave consistently in both scenarios:
 - getting to a branch from and MR (where we already have info about
 relevant MR), or
 - getting to a branch somehow differently directly

For cases where there are several merge requests that the current branch
is associated with, mark the most recent one as 'current'

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/49663

Fix transient dirty submit spec

Closes #58154

See merge request gitlab-org/gitlab-ce!25541

Corrected Spelling Typos

See merge request gitlab-org/gitlab-ce!25717

Docs: Last batch of misc broken anchors

See merge request gitlab-org/gitlab-ce!25707

Fix UI for issuable meta info

Closes #57829

See merge request gitlab-org/gitlab-ce!25332

Minor grammar fix in docker.md documentation

See merge request gitlab-org/gitlab-ce!25640

Docs: Fix all anchors in Admin docs

See merge request gitlab-org/gitlab-ce!25641

Fix a wrong link on group-level cluster doc page

See merge request gitlab-org/gitlab-ce!25693

Update error tracking settings docs

See merge request gitlab-org/gitlab-ce!24924

Show pre-receive error message in merge request widget

Closes gitlab-ee#10165

See merge request gitlab-org/gitlab-ce!25708

When a merge fails due to a locked file, no feedback was given to the
user as to why it failed if the user used the Merge button.  However, if
the push attempt happened directly in the Web UI, the pre-receive
message would be displayed.

To be consistent and to make it clear why a merge failed, we now include
the pre-receive error message in the merge request widget.

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/10165

Removing old code path for search_files_by_content

See merge request gitlab-org/gitlab-ce!25617

Eliminate most N+1 queries loading UserController#calendar_activities

Closes #58392

See merge request gitlab-org/gitlab-ce!25697

In 11.8, we added a fix for the SearchFilesByContent RPC in gitaly to
send back the response in chunks. However, we kept in the old code path
for backwards compatibility. Now that the change is fully deployed, we
can remove that old codepath.

Bump Bootsnap to 1.4.1

See merge request gitlab-org/gitlab-ce!25701

1.4.1 contains a number of bug fixes and performance improvements:
https://github.com/Shopify/bootsnap/blob/master/CHANGELOG.md

Resolve "Github importer ignores Milestone due_date"

Closes #57612

See merge request gitlab-org/gitlab-ce!25182

Fix some 404 links into charts project

See merge request gitlab-org/gitlab-ce!25589

Add quick link to GitLab.com settings

See merge request gitlab-org/gitlab-ce!25580

Add confidential issue linking guidance

See merge request gitlab-org/gitlab-ce!25326

We can reduce a significant number of queries by preloading the
associations for events.

On GitLab.com, for a date that had 456 events, this brought the load
time down from 8.7 to 1.2 s.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/58392

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

Fix GitLab::JsonCache when reading a persisted entry back from the cache

See merge request gitlab-org/gitlab-ce!25587

Hashed Storage rollback mechanism

See merge request gitlab-org/gitlab-ce!23955

Update Serverless docs with livestream feedback

See merge request gitlab-org/gitlab-ce!25616

Add suffix (`_event`) to merge request source

Closes gitlab-ee#9893

See merge request gitlab-org/gitlab-ce!25508

Minor grammar and accuracy fixes

See merge request gitlab-org/gitlab-ce!25665

Add Sentry project dropdown to error tracking settings form

See merge request gitlab-org/gitlab-ce!24701

- Move some specs into contexts
- Let get_slugs method take a parameter and return a specific slug.
- Add rescues when using Addressable::URI.