message: Fix unresolved link in docs
diff: @@ -89,6 +89,7 @@ pub enum Error {
  /// The server did not respond with [`SWITCHING_PROTOCOLS`] status when upgrading the
  /// connection.
  + ///
  /// [`SWITCHING_PROTOCOLS`]: http::status::StatusCode::SWITCHING_PROTOCOLS
  #[cfg(feature = "ws")]
  #[cfg_attr(docsrs, doc(cfg(feature = "ws")))]
  