Messages from the bpy.types.Window class were blacklisted in the
message extraction script.
This change allows a few new messages to be translated, including at
least two which show up in the UI. There are only 12 new messages in
the .po files, so even if some never need to be translated, that's not
too many.
Ref. T43295
Reviewed By: mont29
Differential Revision: https://developer.blender.org/D15628
a2bdd6a71a