bash: Support git-bisect and its subcommands.
bash: Support git-bisect and its subcommands.

We now offer completion support for git-bisect's subcommands,
as well as ref name completion on the good/bad/reset subcommands.
This should make interacting with git-bisect slightly easier on
the fingers.

Signed-off-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git