Use new ogp_canonical_url setting

Author: AA-Turner

Doc/conf.py

@@ -624,7 +624,7 @@
 # Options for sphinxext-opengraph
 # -------------------------------
 
-ogp_site_url = 'https://docs.python.org/3/'
+ogp_canonical_url = 'https://docs.python.org/3/'
 ogp_site_name = 'Python documentation'
 ogp_social_cards = {  # Used when matplotlib is installed
     'image': '_static/og-image.png',