[BUGFIX] Correct wrong class names in deprecation.rst

Correct two class names, one wrongly named, one with a typo, in
a deprecation rst file of 8.0.

Resolves: #73514
Releases: master, 8.7
Change-Id: I48a4af12749d477b151a4774f8e35c09bc9817ce
Reviewed-on: https://review.typo3.org/54944


Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>