including refactoring, disabling sourcepos for pipelines that
don't need it, and minimizing spec changes by disabling
sourcepos when not testing for it explicitly.
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.
Removes the following filters from its parent GfmPipeline:
- SyntaxHighlightFilter
- UploadLinkFilter
- TableOfContentsFilter
- LabelReferenceFilter
- TaskListFilter
Closes#1697