core: Tweak deprecation wording

I know "not supported" and "deprecated" can mean the same, but I
usually read the following meaning into it:

- deprecation ~= don't use this, it will stop working in the future
- not supported ~= don't use this, it already stopped working

Thus I try to only use the "deprecated" term.

mopidy/core/tracklist.py

@@ -554,7 +554,7 @@ class TracklistController(object):
         :rtype: list of :class:`mopidy.models.TlTrack` that was removed
 
         .. deprecated:: 1.1
-            Providing the criteria  via ``kwargs`` is no longer supported.
+            Providing the criteria  via ``kwargs``.
         """
         if kwargs:
             deprecation.warn('core.tracklist.remove:kwargs_criteria')