Refer to channels busy with funding tx negotiation as "unfunded"

We had some inconsistencies so far in referring to channels such as
`OutboundV1Channel` and `InboundV1Channel` as pending and unfunded.
From here we refer to these kinds of channels only as "unfunded".

This is a slight conflation with the term "unfunded" in the contexts
of denial of service mitigation. There, "unfunded" actually refers to
non-0conf, inbound channels that have not had their funding transaction
confirmed. This might warrant changing that usage to "unconfirmed inbound".

Author: dunxen

lightning/src/ln/channelmanager.rs

@@ -685,7 +685,7 @@ impl <Signer: ChannelSigner> PeerState<Signer> {
 			&& self.in_flight_monitor_updates.is_empty()
 	}
 
-	// Returns a count of all channels we have with this peer, including pending channels.
+	// Returns a count of all channels we have with this peer, including unfunded channels.
 	fn total_channel_count(&self) -> usize {
 		self.channel_by_id.len() +
 			self.outbound_v1_channel_by_id.len() +