Clarify that filtering doesn't work for Bugzilla

bugwarrior/docs/services/bugzilla.rst

@@ -29,11 +29,16 @@ make bugwarrior support more robust!
 The above example is the minimum required to import issues from
 Bugzilla.  You can also feel free to use any of the
 configuration options described in :ref:`common_configuration_options`.
+Note, however, that the filtering options, including ``only_if_assigned``
+and ``also_unassigned``, do not work
 
-There is also an option to ignore bugs that you are only cc'd on::
+There is an option to ignore bugs that you are only cc'd on::
 
     bugzilla.ignore_cc = True
 
+But this will continue to include bugs that you reported, regardless of
+whether they are assigned to you.
+
 Provided UDA Fields
 -------------------