API: make promise of removal date

tacaswell · tacaswell · commit 74b45ffcba5a · 2021-11-21T19:07:34.000-05:00
We should have pulled this out in mpl3.5
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -1640,7 +1640,7 @@ def wrapper(*args, **kwargs):
             if arg in accepted_kwargs:
                 continue
             _api.warn_deprecated(
-                '3.3', name=name,
+                '3.3', name=name, removal='3.6',
                 message='%(name)s() got unexpected keyword argument "'
                         + arg + '" which is no longer supported as of '
                         '%(since)s and will become an error '
