Removing youcanhelp stuff

This was never used. It doesn't support Texinfo files. It was only half
completed. Best to remove it.

docs/source/conf.py

@@ -25,7 +25,7 @@ sys.path.insert(0, 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 = ["mgext.youcanhelp"]
+extensions = []
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['source/_templates']