Update git submodules

* Update helpcontent2 from branch 'master'
  - Mute Pootle complain on reserved words
    
    Change-Id: I8e0832a8be6a5118aa1d8b306a250a87434088ca
    Reviewed-on: https://gerrit.libreoffice.org/68252
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 172b0593

-Subproject commit 45899930d0fc91724fba403a2429b9863d32247c
+Subproject commit 172b0593aa4278ce45a758034093077392c0bf90