out.py: switch .info() and .note() to use stderr

In POSIX tradition, informational messages that are not essential output
belong on stderr. Semantically, it appears as if both .info() and
.note() are used for such messages, so switch them to that stream.

Author: jnsnow

stgit/out.py

@@ -127,10 +127,10 @@ def err_bytes(self, byte_data):
 
     def info(self, *msgs):
         for msg in msgs:
-            self.__out.single_line(msg)
+            self.__stderr.single_line(msg)
 
     def note(self, *msgs, **kw):
-        self.__out.tagged_lines(kw.get('title', 'Notice'), msgs)
+        self.__stderr.tagged_lines(kw.get('title', 'Notice'), msgs)
 
     def warn(self, *msgs, **kw):
         self.__stderr.tagged_lines(kw.get('title', 'Warning'), msgs)