[TASK] Fix typos in EXT:form

Fix some typos
Change-Id: Ic45dd7accfde5f024182f55a74d0c0409246c913
Resolves: #70025
Releases: master
Reviewed-on: http://review.typo3.org/43515


Reviewed-by: Frans Saris <franssaris@gmail.com>
Tested-by: Frans Saris <franssaris@gmail.com>
Reviewed-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Tested-by: Bjoern Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Ralf Zimmermann <ralf.zimmermann@tritum.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>