Merge pull request matplotlib#23666 from greglucas/macosx-dep-subplots

MNT: Deprecate macosx prepare subplots tool

Author: jklymak

doc/api/next_api_changes/deprecations/23665-GL.rst

@@ -0,0 +1,4 @@
+The macosx backend toolbar ``prepare_configure_subplots``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+ has been replaced by ``configure_subplots()``.

lib/matplotlib/backends/backend_macosx.py

@@ -132,6 +132,7 @@ def save_figure(self, *args):
             mpl.rcParams['savefig.directory'] = os.path.dirname(filename)
         self.canvas.figure.savefig(filename)
 
+    @_api.deprecated("3.6", alternative='configure_subplots()')
     def prepare_configure_subplots(self):
         toolfig = Figure(figsize=(6, 3))
         canvas = FigureCanvasMac(toolfig)