Add html_entities import stubs to six.moves.

third_party/3/six/moves/__init__.pyi

@@ -24,6 +24,7 @@ from builtins import zip as zip
 from itertools import zip_longest as zip_longest
 import six.moves.cPickle as cPickle
 import html.parser as html_parser
+import html.entities as html_entities
 
 import six.moves.urllib_parse as urllib_parse
 import six.moves.urllib_error as urllib_error