Clean up handshake timeout disconnection log message

It currently reads "disconnected from peer which hasn't completed
handshake due to ping timeout", which is confusing.

Instead, it will now read "disconnected from peer which hasn't
completed handshake due to ping/handshake timeout"

Author: TheBlueMatt

lightning/src/ln/peer_handler.rs

@@ -2103,7 +2103,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 						if let Some((node_id, _)) = peer.their_node_id {
 							self.node_id_to_descriptor.lock().unwrap().remove(&node_id);
 						}
-						self.do_disconnect(descriptor, &*peer, "ping timeout");
+						self.do_disconnect(descriptor, &*peer, "ping/handshake timeout");
 					}
 				}
 			}