src/tutorials/ping: Fix typo in multiaddress
//! over time as interfaces become available or unavailable.
//! For example, in case of our TCP transport it may (among others) listen on the
//! loopback interface (localhost) `/ip4/127.0.0.1/tcp/24915` as well as the local
-//! network `/ip4/192.168.178.25tcp/24915`.
+//! network `/ip4/192.168.178.25/tcp/24915`.
//!
//! In addition, if provided on the CLI, let's instruct our local node to dial a
//! remote peer.
