src/tutorials/hole-punching: Correct commands to use ip4 instead of dns4
//! On the listening client machine:
//!
//! ``` bash
-//! RUST_LOG=info ./client --secret-key-seed 1 --mode listen --relay-address /dns4/$RELAY_SERVER_IP/tcp/4001/p2p/12D3KooWDpJ7As7BWAwRMfu1VU2WCqNjvq387JEYKDBj4kx6nXTN
+//! RUST_LOG=info ./client --secret-key-seed 1 --mode listen --relay-address /ip4/$RELAY_SERVER_IP/tcp/4001/p2p/12D3KooWDpJ7As7BWAwRMfu1VU2WCqNjvq387JEYKDBj4kx6nXTN
//! ```
//!
//! Now let's make sure that the listening client is not public, in other words let's make sure one
//! ## Connecting to the listening client from the dialing client
//!
//! ``` bash
-//! RUST_LOG=info ./client --secret-key-seed 2 --mode dial --relay-address /dns4/$RELAY_SERVER_IP/tcp/4001/p2p/12D3KooWDpJ7As7BWAwRMfu1VU2WCqNjvq387JEYKDBj4kx6nXTN --remote-peer-id 12D3KooWPjceQrSwdWXPyLLeABRXmuqt69Rg3sBYbU1Nft9HyQ6X
+//! RUST_LOG=info ./client --secret-key-seed 2 --mode dial --relay-address /ip4/$RELAY_SERVER_IP/tcp/4001/p2p/12D3KooWDpJ7As7BWAwRMfu1VU2WCqNjvq387JEYKDBj4kx6nXTN --remote-peer-id 12D3KooWPjceQrSwdWXPyLLeABRXmuqt69Rg3sBYbU1Nft9HyQ6X
//! ```
//!
//! You should see the following logs appear:
