Remove references to glium (#5626)

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* Remove references to `glium` backend, because it is deprecated since
egui v0.18.0
* [x] I have followed the instructions in the PR template

crates/eframe/src/native/file_storage.rs

@@ -96,7 +96,7 @@ fn roaming_appdata() -> Option<PathBuf> {
 // ----------------------------------------------------------------------------
 
 /// A key-value store backed by a [RON](https://github.com/ron-rs/ron) file on disk.
-/// Used to restore egui state, glium window position/size and app state.
+/// Used to restore egui state, glow window position/size and app state.
 pub struct FileStorage {
     ron_filepath: PathBuf,
     kv: HashMap<String, String>,