Qt: Fix render widget not being on top when using -n / -e

Source/Core/DolphinQt2/MainWindow.h

@@ -58,6 +58,8 @@ public:
   explicit MainWindow(std::unique_ptr<BootParameters> boot_parameters);
   ~MainWindow();
 
+  void Show();
+
   bool eventFilter(QObject* object, QEvent* event) override;
 
 signals: