DOC: Enable intersphinx

Author: effigies

doc/source/conf.py

@@ -63,7 +63,7 @@
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = ['sphinx.ext.autodoc',
               'sphinx.ext.doctest',
-              #'sphinx.ext.intersphinx',
+              'sphinx.ext.intersphinx',
               'sphinx.ext.todo',
               'sphinx.ext.mathjax',
               'sphinx.ext.inheritance_diagram',
@@ -271,7 +271,7 @@
 
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {'https://docs.python.org/': None}
+intersphinx_mapping = {'https://docs.python.org/3/': None}
 
 # Config of plot_directive
 plot_include_source = True