message: Link to asynk module instead of async-nats
diff: //! system for cloud native applications, `IoT` messaging, and microservices
  //! architectures.
  //!
  -//! For async API refer to the [`async-nats`] crate.
  +//! For async API refer to the [`asynk`] module.
  //!
  //! For more information see [https://nats.io/].
  //!
  //! [https://nats.io/]: https://nats.io/
  -//! [`async-nats`]: https://docs.rs/async-nats
  +//! [`async`]: crate::async
  //!
  //! ## Examples
  //!
  