[BUGFIX][DOC] Builder name t3html not registered

Change-Id: Ife02f290924c2619804ef5ff605dbf32c46ece0b
Reviewed-on: http://review.typo3.org/32369
Reviewed-by: Xavier Perseguers <xavier@typo3.org>
Tested-by: Xavier Perseguers <xavier@typo3.org>