[TASK] Refer to classes in typo3fluid in Changelog

The changelog about removing classes from `ext:fluid` is changed
to refer to the classes in typo3fluid. This should ease migration.

Resolves: #89753
Releases: master, 9.5
Change-Id: Ibf2ce1194427d5b13dca6b7702d3c582813c5b97
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62414


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Sybille Peters <sypets@gmx.de>
Tested-by: Susanne Moog <look@susi.dev>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Susanne Moog <look@susi.dev>