--- a/mercurial/commands.py	Fri Jul 29 00:39:27 2011 +0200
+++ b/mercurial/commands.py	Sat Jul 30 11:08:45 2011 +0100
@@ -2229,6 +2229,7 @@
     :``%R``: changeset revision number
     :``%b``: basename of the exporting repository
     :``%h``: short-form changeset hash (12 hexadecimal digits)
+    :``%m``: first line of the commit message (only alphanumeric characters)
     :``%n``: zero-padded sequence number, starting at 1
     :``%r``: zero-padded changeset revision number