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

The messages are:
"Open window"
"Window height"
"Parent Window"
"Active workspace and scene follow this window"
"Active scene to be edited in the window"
"Active workspace screen showing in the window"
"Active View Layer"
"The active workspace view layer showing in the window"
"Window width"
"Active workspace showing in the window"
"Horizontal location of the window"
"Vertical location of the window"