Misc peer_handler.rs cleanups and fixes

lightning/src/ln/channel.rs

@@ -6024,13 +6024,13 @@ where
 		2*(1 + 71); // two signatures + sighash type flags
 		if let Some(spk) = a_scriptpubkey {
 			ret += ((8+1) +                                    // output values and script length
-				spk.len() as u64)
-				* 4; // scriptpubkey and witness multiplier
+				spk.len() as u64)                              // scriptpubkey
+				* 4; // witness multiplier
 		}
 		if let Some(spk) = b_scriptpubkey {
 			ret += ((8+1) +                                    // output values and script length
-				spk.len() as u64)
-				* 4; // scriptpubkey and witness multiplier
+				spk.len() as u64)                              // scriptpubkey
+				* 4; // witness multiplier
 		}
 		ret
 	}

lightning/src/ln/msgs.rs

@@ -1933,9 +1933,11 @@ pub trait BaseMessageHandler {
 
 	/// Handle a peer (re)connecting.
 	///
-	/// May return an `Err(())` if the features the peer supports are not sufficient to communicate
-	/// with us. Implementors should be somewhat conservative about doing so, however, as other
-	/// message handlers may still wish to communicate with this peer.
+	/// May return an `Err(())` to indicate that we should immediately disconnect from the peer
+	/// (e.g. because the features they support are not sufficient to communicate with us).
+	///
+	/// Note, of course, that other message handlers may wish to communicate with the peer, which
+	/// disconnecting them will prevent.
 	///
 	/// [`Self::peer_disconnected`] will not be called if `Err(())` is returned.
 	fn peer_connected(&self, their_node_id: PublicKey, msg: &Init, inbound: bool)