Add: data parameter in Window::Close method.

This allows passing data when closing a window, e.g. to indicate how it was closed.

src/town_gui.cpp

@@ -364,7 +364,7 @@ public:
 		this->SetWidgetDisabledState(WID_TV_CHANGE_NAME, _networking && !_network_server);
 	}
 
-	void Close() override
+	void Close([[maybe_unused]] int data = 0) override
 	{
 		SetViewportCatchmentTown(Town::Get(this->window_number), false);
 		this->Window::Close();