[TASK] Code cleanup RenameFileController.php

backend/Classes/Controller/File/RenameFileController.php
To get it "green" in PhpStorm several changes are made:

- set correct parameter type in PhpDoc comment
- set correct return type in PhpDoc comment
- add getter for LanguageService
- add getter for DocumentTemplate

Resolves: #65426
Releases: master
Change-Id: I1794d12fed33ab06d460c043632139bc30682a76
Reviewed-on: http://review.typo3.org/37398


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>