Add sphinx.ext.intersphinx.

Author: RKrahl

doc/src/conf.py

@@ -31,6 +31,7 @@
 # ones.
 extensions = [
     'sphinx.ext.autodoc',
+    'sphinx.ext.intersphinx',
 ]
 
 # Add any paths that contain templates here, relative to this directory.
@@ -65,6 +66,15 @@
 
 autodoc_member_order = 'bysource'
 
+
+# -- Options for intersphinx extension ---------------------------------------
+
+intersphinx_mapping = {
+    'python': ('https://docs.python.org/3', None),
+    'pytest': ('https://docs.pytest.org/en/stable/', None),
+}
+
+
 # -- Options for HTML output -------------------------------------------------
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for