As requested by the doc team here is a bug to track what needs updating in the gedit manual.

First of all it needs to be brought up to date: the current manual was last updated with gedit 2.8 or 2.10 (don't recall exactly) and even if gedit UI has not changed radically, some things needs to be synced with the current version.
Out of the top of my head:
 - new side pane
 - new bottom pane
 - some menus may have changed slightly
 - gedit can now save to remote locations
 - search now has highlighting
 - document interactive search (ctrl+K)
 - plugins
   * some plugins were dropped
   * some new plugins were added
     + external tools and 'snippets' in particular are two very powerful plugins  that need docs (there are some on the wiki)


Other than that I guess that there is the "usual stuff" (update screenshots, correct style issues etc)