Overwrite announce fix for #2166 with py2-compatible version

Forgot that I'd prepared a separate branch for the 7.x series.

Author: dgw

test/modules/test_modules_announce.py

@@ -1,5 +1,6 @@
+# coding=utf-8
 """Tests for Sopel's ``announce`` plugin"""
-from __future__ import generator_stop
+from __future__ import absolute_import, division, print_function, unicode_literals
 
 from sopel.modules import announce