desktop: Associate Ruffle window with Ruffle

This patch associates the main window created by Ruffle with the Ruffle
application by its ID.

This fixes issues on some desktops (KDE, Wayland) where the window is
not being recognized as Ruffle.

desktop/src/app.rs

@@ -439,12 +439,18 @@ impl ApplicationHandler<RuffleEvent> for App {
             let preferred_height = self.preferences.cli.height;
             let start_fullscreen = self.preferences.cli.fullscreen;
 
-            let window_attributes = WindowAttributes::default()
+            let mut window_attributes = WindowAttributes::default()
                 .with_visible(false)
                 .with_title("Ruffle")
                 .with_window_icon(Some(icon))
                 .with_min_inner_size(min_window_size);
 
+            #[cfg(target_os = "linux")]
+            {
+                use winit::platform::wayland::WindowAttributesExtWayland;
+                window_attributes = window_attributes.with_name("rs.ruffle.Ruffle", "main");
+            }
+
             let event_loop_proxy = self.event_loop_proxy.clone();
             let preferences = self.preferences.clone();
             let window = event_loop