[BUGFIX] Scheduler to show checkbox if "bool" typehint used in Controller

Until now if you wanted to use a checkbox you had to use "boolean" in that
typehint. If you used "bool" EXT:scheduler output a common input field. As
it seems to be encouraged by the TYPO3 core team to use "bool" PHPDoc
blocks, this commit makes sure that EXT:scheduler will also output a
checkobx if you use "bool" typehints.

Resolves: #76500
Releases: master, 7.6
Change-Id: Ie371e88e3a8e0a23d0cae2f893c5e7f14323068c
Reviewed-on: https://review.typo3.org/48485


Reviewed-by: Mathias Brodala <mbrodala@pagemachine.de>
Tested-by: Mathias Brodala <mbrodala@pagemachine.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>