A user viewing the TODOs page will see a 404 if there are mentioned labels
in multiple different projects. This is likely a caching bug and only occurs
when Markdown rendering occurs across multiple projects, which is why it's so
tricky to reproduce. This is what I think is happening:

1. LabelReferenceFilter#references_in encounters label ~X for ProjectA and finds the label in the DB as id = 1.
2. LabelReferenceFilter.references_in yields [1, 'X', nil, ...]
3. Since project_ref is nil, AbstractReferenceFilter#project_from_ref_cache caches nil => ProjectA.
4. LabelReferenceFilter#references_in encounters label ~Y for ProjectB and finds the label in the DB as id = 2.
5. LabelReferenceFilter.references_in yields [2, 'Y', nil, ...]
6. AbstractReferenceFilter#project_from_ref_cache lookups nil and returns ProjectA. It was supposed to be ProjectB.
7. A is the wrong project, so the label lookup fails.

This MR caches Markdown references if the key is present.

Closes #17898

New style for close buttons

## What does this MR do?
Adds new style for all `Close` buttons

## What are the relevant issue numbers?
Closes #17756 
## Screenshots (if relevant)   
<img src="/uploads/a1d4cb8c22facb4c170e9cf3b4ae439a/Screen_Shot_2016-05-31_at_2.26.42_PM.png" width="800px">   
<img src="/uploads/d567694d79ec6bd5da0ff2faf8b262b0/Screen_Shot_2016-05-31_at_2.26.09_PM.png" width="800px">   
<img src="/uploads/f5e23d8031427079a334d4e03da466b0/Screen_Shot_2016-05-31_at_2.29.01_PM.png" width="800px">   


cc @dzaporozhets 


See merge request !4388

Upgrade Kaminari from 0.16.3 to 0.17.0.

Changelog: https://github.com/amatsuda/kaminari/blob/master/CHANGELOG.rdoc#0170

Deprecates `num_pages` in favor of `total_pages` and includes Rails 5 support.

Working towards #14286.

See merge request !4387

Create the specified remote directory during backup

This is idempotent, so there's no harm calling it if the directory
already exists.

Closes #12710

See merge request !4383

Changelog: https://github.com/amatsuda/kaminari/blob/master/CHANGELOG.rdoc#0170

Deprecates num_pages in favor of total_pages and includes Rails 5 support.

Remove redundant factory namespace in build specs

Extracted from !4351.

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4351#note_12154604

See merge request !4373

Include Wiki attributes in Wiki page events webhook

The hook data we are sending is not 100% correct (we send details of the project, but should also send details of the "ProjectWiki" attributes like URLs and repositories relative to the wiki itself).

This is a follow up to #17506

Fixes #17507

See merge request !4138

This is idempotent, so there's no harm calling it if the directory
already exists.

Closes #12710

Remove project notification settings associated with deleted projects

On GitLab.com, there are 1560 project notification settings with no valid project all created on 2016-04-15 10:38:53 for some reason. This migration should purge
those entries.
    
b8f38437 should prevent this issue from occurring in the first place.
    
Closes gitlab-com/support-forum#678


See merge request !4311

On GitLab.com, there are 1560 project notification settings with no valid project
all created on 2016-04-15 10:38:53 for some reason. This migration should purge
those entries.

b8f38437 should prevent this issue from occurring in the first place.

Closes gitlab-com/support-forum#678

Add Application Setting to configure Container Registry token expire delay (default 5min)

This adds an option to configure Container Registry token expire delay. The default is set to 5mins (something that is also used by Docker Hub).

What is left:
* [x] Write test to check the expire_delay

Fixes: https://gitlab.com/gitlab-org/gitlab-ce/issues/17890

@stanhu I think that this should land in patch release of 8.8.

See merge request !4364

Added "wiki" section and removed "repository"

This is not needed when we specify a default.

Update docs: previous version is 8.7

The old version is 8.7.

See merge request !4288

Enable Wiki Page events from Webhook admin UI in a Project

* Added UI to enable page wiki events
* Documentation for this event in Webhooks page

Fixes #17506

--- 

![new_webhook_UI](/uploads/63ef24b4ccef13ac7a5fda83e9ce64ad/new_webhook_UI.png)

See merge request !4135

Conflicts:
	spec/models/build_spec.rb

Merge branch 'make-container-registry-authentication-service-compatible-with-older-docker' into 'master'

Make authentication service for Container Registry to be compatible with < Docker 1.11

This removes the usage of `offline_token` which is only present when using `Docker 1.11.x` instead we relay on `scope`. This should make it compatible with any client starting from 1.6 (I did test only 1.8 and up).

Right now we return 403 if unauthorized user doesn't have access to anything. In all other cases we return token, but with empty `access`, which simply disallow requested action.



See merge request !4363

Fix typo

Add missing "of" to CI YAML docs.

[ci skip]

See merge request !4331

Fix various documentation typos and spelling mistakes

[ci skip]

See merge request !4345

Add missing steps in update docs

Fixes #18009

[ci skip]

See merge request !4365

Enable Style/SpaceBeforeComma rubocop cop

No spaces before commas.

See #17478

See merge request !4360

Enable Performance/TimesMap Rubocop cop

Use Array.new with a block instead of `.times.collect` / `.times.map`.

See #17478

See merge request !4357

Enable Style/NegatedIf Rubocop cop

Favor `unless` over `if` for negative conditions (or control flow ||).

```ruby
# bad
do_something if !some_condition
# bad
do_something if not some_condition

# good
do_something unless some_condition
# good
some_condition || do_something
```

See #17478

See merge request !4355

Enable Lint/LiteralInCondition rubocop cop

Detects literals used in conditions.

See #17478

See merge request !4354

Enable Style/MultilineIfThen rubocop cop

Do not use then for multi-line if.

See #7478.

See merge request !4353

Enable Style/MethodDefParentheses rubocop cop

Use def with parentheses when there are parameters.

See #17478

See merge request !4352

Enable Style/IndentAssignment Rubocop style cop

Checks the indentation of the first line of the right-hand-side of a multi-line assignment.

See #17478

See merge request !4348