misc: Use a method to create window titles.

src/Ryujinx/UI/Windows/MainWindow.axaml.cs

@@ -79,7 +79,7 @@ namespace Ryujinx.Ava.UI.Windows
 
             UiHandler = new AvaHostUIHandler(this);
 
-            ViewModel.Title = $"Ryujinx {Program.Version}";
+            ViewModel.Title = App.FormatTitle();
 
             // NOTE: Height of MenuBar and StatusBar is not usable here, since it would still be 0 at this point.
             StatusBarHeight = StatusBarView.StatusBar.MinHeight;