message: Remove unused generic from customizable ops
diff: @@ -110,7 +110,7 @@ class CustomizableOperationGenerator(
  }
  /// Convenience for `map_request` where infallible direct mutation of request is acceptable
  - pub fn mutate_request<E>(self, f: impl FnOnce(&mut #{HttpRequest}<SdkBody>)) -> Self {
  + pub fn mutate_request(self, f: impl FnOnce(&mut #{HttpRequest}<SdkBody>)) -> Self {
  self.map_request(|mut req| {
  f(&mut req);
  Result::<_, Infallible>::Ok(req)
  