In revisions.txt, the '<rev>^' form is mentioned but the '<rev>~' form
is missing. Although both forms are essentially equivalent (they each
get the first parent of the specified revision), we should mention the
latter for completeness. Make this change.
Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>