Fix comment as suggested by @hannosch.

src/ZPublisher/WSGIPublisher.py

@@ -276,7 +276,7 @@ def publish_module(environ, start_response,
             result = response.body
         else:
             # If somebody used response.write, that data will be in the
-            # stdout BytesIO, so we put that before the body.
+            # response.stdout BytesIO, so we put that before the body.
             result = (response.stdout.getvalue(), response.body)
 
         for func in response.after_list: