Fix: Let `accesskit` process window events (#3733)

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Since accesskit_winit version 0.15.0, it is necessary to call
`Adapter::process_events` to let AccessKit fire up window focus events
on Unix and macOS. Furthermore this has always been needed on Unix (X11
only) to let AccessKit know about the window bounds, which is needed to
perform hit-testing on nodes.

crates/egui-winit/src/lib.rs

@@ -236,6 +236,11 @@ impl State {
     ) -> EventResponse {
         crate::profile_function!(short_window_event_description(event));
 
+        #[cfg(feature = "accesskit")]
+        if let Some(accesskit) = &self.accesskit {
+            accesskit.process_event(window, event);
+        }
+
         use winit::event::WindowEvent;
         match event {
             WindowEvent::ScaleFactorChanged { scale_factor, .. } => {