Add success message

ExeLauncher.GUI/MainWindow.xaml.cs

@@ -129,6 +129,10 @@ namespace ExeLauncher.GUI
 
                     MessageBox.Show(message, "Compilation error", MessageBoxButton.OK, MessageBoxImage.Error);
                 }
+                else
+                {
+                    MessageBox.Show($"Successfully generated launcher at: {dialog.FileName}", "Success", MessageBoxButton.OK, MessageBoxImage.Information);
+                }
             }
         }