Mark deprecated modules as such.
diff --git a/Doc/library/rfc822.rst b/Doc/library/rfc822.rst
index fa25ba5..52df013 100644
--- a/Doc/library/rfc822.rst
+++ b/Doc/library/rfc822.rst
@@ -4,6 +4,7 @@
 
 .. module:: rfc822
    :synopsis: Parse 2822 style mail messages.
+   :deprecated:
 
 
 .. deprecated:: 2.3