[TASK] Make Content Element "Special Menus" field bigger

Increase the maxitems value to 50 to allow more values for bigger sites.

Releases: master
Resolves: #59523
Change-Id: Ie25974844bf7ce9f0b7995169964748872eb3f1a
Reviewed-on: http://review.typo3.org/39532


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>