[ci skip]

* Enclose the identifier in strong
* Use the % character as in GFM
* Remove spaces around en dash for date range

* Enclose the identifier in strong
* Use the % character as in GFM
* Remove spaces around en dash for date range

Added subnav to blame show, blob edit, builds show, commit builds, commit show, environments edit and pipelines show

Added subnav to new enviro view

Added sidebar top position calculation logic

Added sidebar translation to follow the subnav up when the body is scrolled until a certain limit

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.