message: feat(engine) Simplify code.
diff: @@ -158,7 +158,7 @@ impl RuntimeError {
  /// Returns a reference the `message` stored in `Trap`.
  pub fn message(&self) -> String {
  - format!("{}", self.inner.source)
  + self.inner.source.to_string()
  }
  /// Returns a list of function frames in WebAssembly code that led to this
  