completion: bisect: complete missing --first-parent and - -no-checkout options

The --first-parent and --no-checkout options to the start subcommand of
git-bisect(1) are not completed.

Enable completion of the --first-parent and --no-checkout options to the
start subcommand.  Add test.

Signed-off-by: Britton Leo Kerin <britton.kerin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/completion/git-completion.bash

@@ -1478,7 +1478,7 @@ _git_bisect ()
 	start)
 		case "$cur" in
 		--*)
-			__gitcomp "--term-new --term-bad --term-old --term-good"
+			__gitcomp "--first-parent --no-checkout --term-new --term-bad --term-old --term-good"
 			return
 			;;
 		*)

t/t9902-completion.sh

@@ -1271,6 +1271,17 @@ test_expect_success 'git bisect - when not bisecting, complete only replay and s
 	EOF
 '
 
+test_expect_success 'git bisect - complete options to start subcommand' '
+	test_completion "git bisect start --" <<-\EOF
+	--term-new Z
+	--term-bad Z
+	--term-old Z
+	--term-good Z
+	--no-checkout Z
+	--first-parent Z
+	EOF
+'
+
 test_expect_success 'setup for git-bisect tests requiring a repo' '
 	git init git-bisect &&
 	(