[TASK] Take care of rendering warnings in core Changelog rendering

Also, some improvements are made to sentence structure, tenses
and syntax highlightning.

Resolves: #88748
Releases: master, 9.5
Change-Id: I932dabbfc404de7c3dc4f3cef1ccb50c2fd94f72
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61291


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Koen Wouters <koen.wouters@maxserv.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Koen Wouters <koen.wouters@maxserv.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>