fix clippy

src/sounds.rs

@@ -42,7 +42,7 @@ fn spawn_sounds(
             assets
                 .head
                 .get(filename.as_str())
-                .expect(format!("invalid head '{}'", filename).as_str())
+                .unwrap_or_else(|| panic!("invalid head '{}'", filename))
                 .clone()
         }
     };