Create a new man page gitrevisions(7) which contains the revsions and
ranges documentation but not more. This uses (per include) the same bits
as the pertaining section of git-rev-parse(1).
Signed-off-by: NMichael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>