message: Remove `#[doc(hidden)]` from `aws_smithy_http_server::body::BoxBody`
  And from the `boxed` body function.
  These are necessary if users need to implement middleware
  (`tower::Layer`s) that use the request's body.
diff: */
  //! HTTP body utilities.
  +
  +// Used in the codegen in trait bounds.
  #[doc(hidden)]
  pub use http_body::Body as HttpBody;
  -#[doc(hidden)]
  pub use hyper::body::Body;
  use bytes::Bytes;
  use crate::error::{BoxError, Error};
  -#[doc(hidden)]
  pub type BoxBody = http_body::combinators::UnsyncBoxBody<Bytes, Error>;
  // `boxed` is used in the codegen of the implementation of the operation `Handler` trait.
  /// Convert a [`http_body::Body`] into a [`BoxBody`].
  -#[doc(hidden)]
  pub fn boxed<B>(body: B) -> BoxBody
  where
  B: http_body::Body<Data = Bytes> + Send + 'static,
  