Merge pull request matplotlib#20726 from larsoner/dep-doc

DOC: Provide alternative to cbar.patch

Author: story645

lib/matplotlib/colorbar.py

@@ -489,7 +489,7 @@ def __init__(self, ax, mappable=None, *, cmap=None,
             self.add_lines(mappable)
 
     # Also remove ._patch after deprecation elapses.
-    patch = _api.deprecate_privatize_attribute("3.5")
+    patch = _api.deprecate_privatize_attribute("3.5", alternative="ax")
 
     def update_normal(self, mappable):
         """