Fix backspace/arrow keys in TextEdit on Linux (#5188)

* Closes https://github.com/emilk/egui/issues/5008
* Closes https://github.com/emilk/egui/pull/5182
* Bug introduced in https://github.com/emilk/egui/pull/4912

I suspect this will make IME no longer work on Linux, though I don't
know if it ever worked.
I rather have backspace/arrows working though.

Please help test this (I don't have Linux!)

# Tested on
* [x] Mac
* [ ] Linux Wayland
* [x] Linux X11

crates/egui-winit/src/lib.rs

@@ -329,6 +329,9 @@ impl State {
             }
 
             WindowEvent::Ime(ime) => {
+                if cfg!(target_os = "linux") {
+                    // We ignore IME events on linux, because of https://github.com/emilk/egui/issues/5008
+                } else {
                     // on Mac even Cmd-C is pressed during ime, a `c` is pushed to Preedit.
                     // So no need to check is_mac_cmd.
                     //
@@ -362,6 +365,7 @@ impl State {
                             self.ime_event_disable();
                         }
                     };
+                }
 
                 EventResponse {
                     repaint: true,