Replace #[allow attributes with expect (#7796)

We do have `clippy::allow_attributes` turned on, but it doesn't seem to
work properly

crates/egui_demo_app/src/apps/custom3d_glow.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::undocumented_unsafe_blocks)]
+#![expect(clippy::undocumented_unsafe_blocks)]
 
 use std::sync::Arc;
 

crates/egui_demo_app/src/main.rs

@@ -1,8 +1,8 @@
 //! Demo app for egui
 
 #![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
-#![allow(rustdoc::missing_crate_level_docs)] // it's an example
-#![allow(clippy::never_loop)] // False positive
+#![expect(rustdoc::missing_crate_level_docs)] // it's an example
+#![allow(clippy::allow_attributes, clippy::never_loop)]
 
 #[global_allocator]
 static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc; // Much faster allocator, can give 20% speedups: https://github.com/emilk/egui/pull/7029

crates/egui_demo_app/src/web.rs

@@ -1,5 +1,3 @@
-#![allow(clippy::mem_forget)] // False positives from #[wasm_bindgen] macro
-
 use eframe::wasm_bindgen::{self, prelude::*};
 
 use crate::WrapApp;
@@ -14,7 +12,7 @@ pub struct WebHandle {
 #[wasm_bindgen]
 impl WebHandle {
     /// Installs a panic hook, then returns.
-    #[allow(clippy::new_without_default, clippy::allow_attributes)]
+    #[allow(clippy::allow_attributes, clippy::new_without_default)]
     #[wasm_bindgen(constructor)]
     pub fn new() -> Self {
         // Redirect [`log`] message to `console.log` and friends:

crates/egui_demo_app/src/wrap_app.rs

@@ -183,7 +183,7 @@ impl WrapApp {
         cc.egui_ctx
             .add_plugin(crate::accessibility_inspector::AccessibilityInspectorPlugin::default());
 
-        #[allow(unused_mut, clippy::allow_attributes)]
+        #[allow(clippy::allow_attributes, unused_mut)]
         let mut slf = Self {
             state: State::default(),