mod_groups_muc_bookmarks: fix typo/leftover from refactor The update_bookmark function no longer takes a "current" argument; passing it causes havoc in service:publish (because it gets the room JID instaed of the item as item).

---
summary: Log a message once per minute
...

This module sends `-- MARK --` to the log once per minute. This may be
useful to give a sense of how busy the server is or see that logging and
timers are still working.