[lua] add override for FileOutput.close

std/lua/_std/sys/io/FileOutput.hx

@@ -47,4 +47,8 @@ class FileOutput extends haxe.io.Output {
 		f.write(String.fromCharCode(c));
 	}
 
+	override public function close() {
+		f.close();
+	}
+
 }