Documentation/bisect: improve on (bad|new) and (good|bad)

The following part of the description: git bisect (bad|new) [<rev>] git bisect (good|old) [<rev>...] may be a bit confusing, as a reader may wonder if instead it should be: git bisect (bad|good) [<rev>] git bisect (old|new) [<rev>...] Of course the difference between "[<rev>]" and "[<rev>...]" should hint that there is a good reason for the way it is. But we can further clarify and complete the description by adding "<term-new>" and "<term-old>" to the "bad|new" and "good|old" alternatives. Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>