Prevent `clippy` complaining at method

It's not incorrectly wrapped. We care about the return type being `Option`.

src/error.rs

@@ -152,6 +152,7 @@ impl<S> MapResult<S> for Option<S> {
     }
 }
 
+#[allow(clippy::unnecessary_wraps)]
 const fn _has_source<T>(e: T) -> Option<T> {
     Some(e)
 }