merge-recursive: use "up-to-date" instead of "uptodate" in error message for consistency

Signed-off-by: Nicolas Sebrecht <nicolas.s.dev@gmx.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge-recursive.c

@@ -1214,7 +1214,7 @@ int merge_trees(struct merge_options *o,
 	}
 
 	if (sha_eq(common->object.sha1, merge->object.sha1)) {
-		output(o, 0, "Already uptodate!");
+		output(o, 0, "Already up-to-date!");
 		*result = head;
 		return 1;
 	}