message: update if / if-let in rustdoc
diff: @@ -284,7 +284,8 @@ impl RustdocPage {
  let mut response = Response::with((Status::Ok, html));
  response.headers.set(ContentType::html());
  - if let Some(cache_control) = if is_latest_url {
  +
  + let cache_control = if is_latest_url {
  generate_cache_directives_for(
  Some(config.cache_control_max_age_latest.unwrap_or(0)),
  config.cache_control_stale_while_revalidate_latest,
  @@ -294,7 +295,8 @@ impl RustdocPage {
  config.cache_control_max_age,
  config.cache_control_stale_while_revalidate,
  )
  - } {
  + };
  + if let Some(cache_control) = cache_control {
  response.headers.set(cache_control);
  }
  Ok(response)
  