FIX: Remove unused and broken intersphinx mapping

src/doc/conf.py

@@ -196,7 +196,7 @@ primary_domain = 'js'  # Not strictly necessary?
 # -- Options for intersphinx extension ---------------------------------------
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {'https://docs.python.org/': None}
+intersphinx_mapping = {}
 
 # TODO Which options do we want?
 autodoc_default_options = {