git-jump: give contact instructions in the README

Let's make it clear how patches should flow into
contrib/git-jump. The normal Git maintainer does not
necessarily care about things in contrib/, and authors of
individual components should be the ones giving the final
review/ack for a patch. Ditto for bug reports, which are
likely to get more attention from the area expert.

Signed-off-by: Jeff King <peff@peff.net>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/git-jump/README

@@ -95,3 +95,10 @@ how to activate it.
 
 The shell snippets to generate the quickfix lines will almost certainly
 choke on filenames with exotic characters (like newlines).
+
+Contributing
+------------
+
+Bug fixes, bug reports, and feature requests should be discussed on the
+Git mailing list <git@vger.kernel.org>, and cc'd to the git-jump
+maintainer, Jeff King <peff@peff.net>.