[FOLLOWUP][TASK] Deprecate some functions not in use anymore in the core

Update the RST file

Resolves: #72851
Releases: master
Change-Id: I4258be69fd69a698f323854bd9caaa633c5e4807
Reviewed-on: https://review.typo3.org/46147


Reviewed-by: Michael Oehlhof <typo3@oehlhof.de>
Tested-by: Michael Oehlhof <typo3@oehlhof.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>