message: Fix doc comment for the new set_reconnect_delay_callback function
diff: @@ -516,9 +516,15 @@ impl<TypeState> ConnectionOptions<TypeState> {
  self
  }
  - /// Set a callback to be executed when the client has been
  - /// closed due to exhausting reconnect retries to known servers
  - /// or by completing a drain request.
  + /// Set a callback to be executed for calculating the backoff duration
  + /// to wait before a server reconnection attempt.
  + ///
  + /// The function takes the number of reconnects as an argument
  + /// and returns the `Duration` that should be waited before
  + /// making the next connection attempt.
  + ///
  + /// It is recommended that some random jitter is added to
  + /// your returned `Duration`.
  pub fn set_reconnect_delay_callback<F>(mut self, cb: F) -> Self
  where
  F: Fn(usize) -> Duration + Send + Sync + 'static,
  