The rev-parse manpage introduces the branch@{date} syntax,
and mentions the reflog specifically. However, new users may
not be familiar with the distinction between the reflog and
the commit date, so let's help them out with a "you may be
interested in --until" pointer.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>