Fix intersphinx (#1130)

Author: hynek

docs/conf.py

@@ -159,9 +159,7 @@
 
 epub_description = "Python Clases Without Boilerplate"
 
-intersphinx_mapping = {
-    "https://docs.python.org/3": None,
-}
+intersphinx_mapping = {"python": ("https://docs.python.org/3", None)}
 
 # Allow non-local URIs so we can have images in CHANGELOG etc.
 suppress_warnings = ["image.nonlocal_uri"]