receive-pack: improve English grammar of denyCurrentBranch message

The article "the" is required here.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/receive-pack.c

@@ -795,8 +795,8 @@ static char *refuse_unconfigured_deny_msg =
 	   "with what you pushed, and will require 'git reset --hard' to match\n"
 	   "the work tree to HEAD.\n"
 	   "\n"
-	   "You can set 'receive.denyCurrentBranch' configuration variable to\n"
-	   "'ignore' or 'warn' in the remote repository to allow pushing into\n"
+	   "You can set the 'receive.denyCurrentBranch' configuration variable\n"
+	   "to 'ignore' or 'warn' in the remote repository to allow pushing into\n"
 	   "its current branch; however, this is not recommended unless you\n"
 	   "arranged to update its work tree to match what you pushed in some\n"
 	   "other way.\n"