"reset" can be easily misunderstood as resetting a bisect session to its
start without finishing it. Clarify that it actually quits the bisect
session.
Reported-by: Andreas Mohr <andi@lisas.de> Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>