Convert to the superior language system. (pt. 2)

src/main/java/emu/grasscutter/command/commands/CoopCommand.java

@@ -13,7 +13,7 @@ public final class CoopCommand implements CommandHandler {
     @Override
     public void execute(Player sender, Player targetPlayer, List<String> args) {
 		if (targetPlayer == null) {
-			CommandHandler.sendMessage(sender, Grasscutter.getLanguage().Target_needed);
+			CommandHandler.sendMessage(sender, translate("commands.execution.need_target"));
 			return;
 		}