Update mathjax sphinx option

doc/conf.py

@@ -29,7 +29,8 @@ sys.path.append(os.path.abspath('.'))
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = ['sphinx.ext.autodoc', 'sphinx.ext.doctest',
-              'sphinx.ext.intersphinx', 'mathjax', 'sphinx.ext.autosummary',
+              'sphinx.ext.intersphinx', 'sphinx.ext.mathjax',
+              'sphinx.ext.autosummary',
               'numpydoc',
               'sphinx.ext.extlinks',
               'sphinx.ext.viewcode',