Fix: Backspace not working after IME input (#4912)

Fix: Changed the handling method of `Ime::Preedit(_, None)`

Fix: backspace fail after ime input

* Related #4358
* Related #4430 
* Related #4436
* Related #4794 
* Related #4896
* Closes #4908 

Issues: backspace fail after ime input
* #4908 (Chinese)

Changed the handling method of `Ime::Preedit(_, None)`

Author: rustbasic

crates/egui-winit/src/lib.rs

@@ -341,8 +341,7 @@ impl State {
                 // We use input_method_editor_started to manually insert CompositionStart
                 // between Commits.
                 match ime {
-                    winit::event::Ime::Enabled => {}
-                    winit::event::Ime::Preedit(_, None) => {
+                    winit::event::Ime::Enabled => {
                         self.ime_event_enable();
                     }
                     winit::event::Ime::Preedit(text, Some(_cursor)) => {
@@ -357,7 +356,7 @@ impl State {
                             .push(egui::Event::Ime(egui::ImeEvent::Commit(text.clone())));
                         self.ime_event_disable();
                     }
-                    winit::event::Ime::Disabled => {
+                    winit::event::Ime::Disabled | winit::event::Ime::Preedit(_, None) => {
                         self.ime_event_disable();
                     }
                 };