Simplify visualeditor-help-title and visualeditor-timeout

The less repetition and the less undefined concepts where possible,
the more clarity. Suggestions thanks to James' explanations at
* https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Visualeditor-timeout/en
* https://translatewiki.net/wiki/Thread:Support/About_MediaWiki:Visualeditor-help-title/en

Change-Id: I05857e5287f5f15f0206a8faa46922e7aa7c3c1b
Merge "Simplify visualeditor-help-title and visualeditor-timeout"