checkout: add some spaces between code and comment

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/checkout.c

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8672d07..1f71d06 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1038,7 +1038,7 @@ static int parse_branchname_arg(int argc, const char **argv,
 
 	if (!*source_tree)                   /* case (1): want a tree */
 		die(_("reference is not a tree: %s"), arg);
-	if (!has_dash_dash) {/* case (3).(d) -> (1) */
+	if (!has_dash_dash) {	/* case (3).(d) -> (1) */
 		/*
 		 * Do not complain the most common case
 		 *	git checkout branch