Forbid uses of unwrap() in the code (#7795)

examples/hello_world_par/src/main.rs

@@ -1,7 +1,7 @@
 //! This example shows that you can use egui in parallel from multiple threads.
 
 #![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
+#![expect(clippy::unwrap_used)] // it's an example
 
 use std::sync::mpsc;
 use std::thread::JoinHandle;