[BUGFIX] Correct method name in documentation file

The mentioned method to be changed was mistyped.
The name given in the rst file doesn't exist.

Resolves: #77750
Releases: master, 8.7
Change-Id: Ic64590c8ffa3826dd3c5db5365e0c5273e897824
Reviewed-on: https://review.typo3.org/54954


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Susanne Moog <susanne.moog@typo3.org>
Tested-by: Susanne Moog <susanne.moog@typo3.org>