Update git submodules

* Update helpcontent2 from branch 'master'
  - Update DTD for <pycode>
    
    Change-Id: Icbda71715b4c23644699e9963983ab2db7c0074a
    Reviewed-on: https://gerrit.libreoffice.org/65103
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 1405725d

-Subproject commit ff95264637de17c48fa5de9765c97bb103cf077b
+Subproject commit 1405725db5080e22b5567fde2a81610f4e0b0bed