message: docs(client): document the guarantees of cloning a `Client`
  Small docs improvement to mention that cloning a `Client` is cheap and
  will reuse the connection pool.
  Fixes
diff: @@ -19,6 +19,9 @@ use crate::common::{exec::BoxSendFuture, lazy as hyper_lazy, task, Future, Lazy,
  use crate::rt::Executor;
  /// A Client to make outgoing HTTP requests.
  +///
  +/// `Client` is cheap to clone and cloning is the recommended way to share a `Client`. The
  +/// underlying connection pool will be reused.
  #[cfg_attr(docsrs, doc(cfg(any(feature = "http1", feature = "http2"))))]
  pub struct Client<C, B = Body> {
  config: Config,
  