[DOCS] Revise changelogs for v12.0

Resolves: #98368
Releases: main
Change-Id: Ibdda66047e4b6eb55bca4cdbf217d045033e54b5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75750


Tested-by: core-ci <typo3@b13.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>