chore(dns): remove deprecated symbols

Pull-Request: #4739.

Author: thomaseizinger

transports/dns/CHANGELOG.md

@@ -1,9 +1,9 @@
 ## 0.41.0 - unreleased
 
 - Make `tokio::Transport::custom` and `async_std::Transport::custom` constructors infallible.
-  See [PR 4464].
-
-[PR 4464]: https://github.com/libp2p/rust-libp2p/pull/4464
+  See [PR 4464](https://github.com/libp2p/rust-libp2p/pull/4464).
+- Remove deprecated type-aliases.
+  See [PR 4739](https://github.com/libp2p/rust-libp2p/pull/4739). 
 
 ## 0.40.1
 

transports/dns/src/lib.rs

@@ -88,10 +88,6 @@ pub mod async_std {
     }
 }
 
-#[cfg(feature = "async-std")]
-#[deprecated(note = "Use `async_std::Transport` instead.")]
-pub type DnsConfig<T> = async_std::Transport<T>;
-
 #[cfg(feature = "tokio")]
 pub mod tokio {
     use parking_lot::Mutex;
@@ -124,10 +120,6 @@ pub mod tokio {
     }
 }
 
-#[cfg(feature = "tokio")]
-#[deprecated(note = "Use `tokio::Transport` instead.")]
-pub type TokioDnsConfig<T> = tokio::Transport<T>;
-
 use async_trait::async_trait;
 use futures::{future::BoxFuture, prelude::*};
 use libp2p_core::{
@@ -184,9 +176,6 @@ pub struct Transport<T, R> {
     resolver: R,
 }
 
-#[deprecated(note = "Use `async_std::Transport` or `tokio::Transport` instead.")]
-pub type GenDnsConfig<T, R> = Transport<T, R>;
-
 impl<T, R> libp2p_core::Transport for Transport<T, R>
 where
     T: libp2p_core::Transport + Send + Unpin + 'static,
@@ -414,9 +403,6 @@ pub enum Error<TErr> {
     TooManyLookups,
 }
 
-#[deprecated(note = "Use `Error` instead.")]
-pub type DnsErr<TErr> = Error<TErr>;
-
 impl<TErr> fmt::Display for Error<TErr>
 where
     TErr: fmt::Display,