[TASK] Move EXT:lang/locallang_alt_doc.xml to include as xlf

Resolves: #68078
Releases: master
Change-Id: I1cc0abe0a6d0f962472061017a91c7fa8f5f8995
Reviewed-on: http://review.typo3.org/41134


Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>