Fix pub visibility for Trailers

Author: yoshuawuyts

src/lib.rs

@@ -128,9 +128,11 @@ pub use method::Method;
 pub use request::Request;
 pub use response::Response;
 pub use status_code::StatusCode;
-pub use trailers::Trailers;
 pub use version::Version;
 
+#[doc(inline)]
+pub use trailers::Trailers;
+
 #[doc(inline)]
 pub use mime::Mime;