Add api change note for the deprecation of line attribute of PolygonSelector.

Author: ericpre

doc/api/next_api_changes/deprecations/20693-EP.rst

@@ -0,0 +1,4 @@
+PolygonSelector
+^^^^^^^^^^^^^^^
+The *line* attribute is deprecated. If you want to change the selector
+artist properties, use the ``set_props`` or ``set_handle_props`` methods.

lib/matplotlib/widgets.py

@@ -2012,7 +2012,7 @@ def set_visible(self, visible):
     def artists(self):
         """Tuple of the artists of the selector."""
         if getattr(self, '_handles_artists', None) is not None:
-            return (self._selection_artist, ) + self._handles_artists
+            return (self._selection_artist, *self._handles_artists)
         else:
             return (self._selection_artist, )