Update git submodules

* Update helpcontent2 from branch 'master'
  - The <version>/index.html can default correctly, no need to do it in the root.
    
    Change-Id: If74aaea6924638f9fef647121da4a35c66fc0213
    Reviewed-on: https://gerrit.libreoffice.org/59048
    Tested-by: Jenkins
Reviewed-by: Jan Holesovsky <kendy@collabora.com>
    

helpcontent2 @ e76947a2

-Subproject commit 73023bcc0dba68f6677bc02cdad75145180e2b11
+Subproject commit e76947a271da80e60ef658a9795fd95b6f26476a