Closes #31073

This will only hapen in certain situations ie. when the star count is a
lot. We were previously fixing it by hard coding a max-width.

This changes it to use flexbox which allows the content to decide when
it should be truncated. The rows don't always need truncating, so we
shouldn't hard code a width.

Closes #29018

This commit alters views for the following models to use the markdown cache if
present:

* AbuseReport
* Appearance
* ApplicationSetting
* BroadcastMessage
* Group
* Issue
* Label
* MergeRequest
* Milestone
* Project

At the same time, calls to `escape_once` have been moved into the `single_line`
Banzai pipeline, so they can't be missed out by accident and the work is done
at save, rather than render, time.

Closes #19583

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

* Introduce 2 color links: black and blue
* Use black color link for UI elements like lists
* Refactor lists to use .title nested under li
* Make all lists (events, todos, activity, projects etc) use style
* List colorschema is now 333 for links and 555 for text

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

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