[BUGFIX] Fix broken HTML in about modules

fix broken HTML output for headlines in about modules

Resolves: #63094
Releases: master
Change-Id: I2f2e912432353dd05bc0898fc8e9a68d2394664f
Reviewed-on: http://review.typo3.org/34377
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>