Update git submodules

* Update helpcontent2 from branch 'master'
  - Add link to Python pages in Basic main page
    
    Change-Id: If31c609e4d345feec47bb89beac41a0c1ce6eedb
    Reviewed-on: https://gerrit.libreoffice.org/66726
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 9b903d0a

-Subproject commit 2706cb2c41c235a88f87d6bd439e67a5197b8c60
+Subproject commit 9b903d0ab3e992b322816a881360d611b936c678