The overview feature has been removed, because this is already
handled using the dektop actions(forgot to change this in D27109).
Insteadof returning in the match method if the kate sessions are empty,
the matching gets suspended when the sessions are (re)loaded.
Additionally the check if the length of the trigger word is smaller than 3 has been removed
(and considering that the trigger word kate has 4 letters this made not that much sense ;-) ).

Should compile and you can search for sessions like kate <session name>