chore: address some clippy concerns

string-literal/src/lib.rs

@@ -15,7 +15,7 @@ where
 {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let Self { actual, expected } = self;
-        let expected_str = <&'static str>::from(&expected);
+        let expected_str = <&'static str>::from(expected);
 
         write!(f, "expected {expected_str:?} but got {actual:?}")
     }