Update git submodules

* Update helpcontent2 from branch 'master'
  - Monitoring document events with Python & Basic
    
    -Mutual help pages x-refs
    -tree addition
    -new bookmarks for
    --Advanced Basic Libraries
    --Appl. Progr. Interface
    
    NB: I wish I could create new </img> in gerrit
    
    OH:
    moved  new xhp to right position
    New image
    Update makefiles
    several x-ref fixes
    
    libO: Added language-driven <switch/> and <case/> tags for 3 different img captures
    that XHP Editor doesn't propose but that are documented
    Couldn't validate such switches.. crossing fingers..
    
    OH: Languages are not switchable, as explained in comments.
    Removed reference to image for good (not l10n full support).
    fix missing apostrophe.
    
    Change-Id: I97c92fc879df19f9e8de73e828cd3324ba2163fa
    Reviewed-on: https://gerrit.libreoffice.org/70896
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 3f98a5fd

-Subproject commit 7b20c74a33942157b02b99353aa98e45f7c0a111
+Subproject commit 3f98a5fd443d3ff5789e4afa551389d3e2db64c3