dsm: fix typo in doc

thanks to matthew williams for spotting this

doc/dsm/mods/Readme.mod_conference.txt

@@ -21,7 +21,7 @@ conference.teejoin(string roomname [, string avar_id])
    - speak also to conference with roomname
    - avar_id is the name in which conference channel is stored 
    - if this is called in the beginning of a call (sessionStart event, 
-     or initial state enter block), call setPlaylistInOut before 
+     or initial state enter block), call setInOutPlaylist before 
      conference.teejoin (teejoin uses input to connect to audio queue,
      which is normally set only after running sessionStart event in 
      inital state)