Update git submodules

* Update helpcontent2 from branch 'master'
  - Fixed some silliness, added highlighting for index filter
    
    Change-Id: I946ffdb52ed8f324ab58f45a90f5decdd58932dc
    Reviewed-on: https://gerrit.libreoffice.org/63240
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 12cf5b53

-Subproject commit e8b0895cb28ecfdbc054aa26e138f17db6776a03
+Subproject commit 12cf5b53b185177924dd7ce572bc7451c9edc76b