bash completion: complete refs for git-grep
bash completion: complete refs for git-grep

Before the --, always attempt ref completion.  This helps with
entering the <treeish> arguments to git-grep.  As a bonus, you can
work around git-grep's current lack of --all by hitting M-*, ugly as
the resulting command line may be.

Strictly speaking, completing the regular expression argument (or
option argument) makes no sense.  However, we cannot prevent _all_
completion (it will fall back to filenames), so we dispense with any
additional complication to detect whether the user still has to enter
a regular expression.

Signed-off-by: Thomas Rast <18f23ef7096473d837b7404952f13710423b8b63@student.ethz.ch>
Acked-by: Shawn O. Pearce <f01032651c12a22b2103346ba96b3b6b231f9d3c@spearce.org>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

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