Consolidate behavioural API changes for 3.6

Author: QuLogic

doc/api/artist_api.rst

@@ -105,6 +105,7 @@ Drawing
 
    Artist.get_agg_filter
    Artist.get_window_extent
+   Artist.get_tightbbox
    Artist.get_transformed_clip_path_and_affine
 
 Figure and Axes

doc/api/matplotlib_configuration_api.rst

@@ -31,6 +31,7 @@ Default values and styling
    :no-members:
 
    .. automethod:: find_all
+   .. automethod:: copy
 
 .. autofunction:: rc_context