fmt: addressed linter complaints

src/event/key_tests.rs

@@ -24,7 +24,7 @@ mod tests {
   #[case(Key::Char('q'), "q")]
   #[case(Key::Ctrl('q'), "ctrl-q")]
   fn test_key_formatter(#[case] key: Key, #[case] expected_str: &str) {
-    assert_str_eq!(format!("{key}"), format!("{expected_str}"));
+    assert_str_eq!(format!("{key}"), expected_str.to_string());
   }
 
   #[test]