[BUGFIX] Fix phpdoc after namespacing

Fix three occurences of old class names in phpdoc.

Fixes: #46972
Releases: 6.0,6.1
Change-Id: Ia9b37cecf92dd21b8bea83ef351e1006c420b83f
Reviewed-on: https://review.typo3.org/19650
Reviewed-by: Wouter Wolters
Reviewed-by: Magdalena Leichsenring
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn