Update git submodules

* Update helpcontent2 from branch 'master'
  - Fix menu paths Help pages after translators review
    
    Change-Id: I4afa7097d47b186c0f9732f68abadcbd73633042
    Reviewed-on: https://gerrit.libreoffice.org/65487
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 50e18a07

-Subproject commit d439868081611bd0bd1f95da86b10bef49f511ad
+Subproject commit 50e18a0776faca0ecbfa405661e03ef38028b7af