f internal docs

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -5126,7 +5126,9 @@ where
 		}
 	}
 
-	/// Gets the current [`channel_update`] for the given channel. This first checks if the channel is
+	/// Gets the current [`channel_update`] for the given channel (as well as our and our
+	/// counterparty's [`NodeId`], which is needed for the
+	/// [`MessageSendEvent::BroadcastChannelUpdate`]). This first checks if the channel is
 	/// public, and thus should be called whenever the result is going to be passed out in a
 	/// [`MessageSendEvent::BroadcastChannelUpdate`] event.
 	///
@@ -5160,10 +5162,11 @@ where
 		self.get_channel_update_for_unicast(chan)
 	}
 
-	/// Gets the current [`channel_update`] for the given channel. This does not check if the channel
-	/// is public (only returning an `Err` if the channel does not yet have an assigned SCID),
-	/// and thus MUST NOT be called unless the recipient of the resulting message has already
-	/// provided evidence that they know about the existence of the channel.
+	/// Gets the current [`channel_update`] for the given channel (as well as our and our
+	/// counterparty's [`NodeId`]). This does not check if the channel is public (only returning an
+	/// `Err` if the channel does not yet have an assigned SCID), and thus MUST NOT be called
+	/// unless the recipient of the resulting message has already provided evidence that they know
+	/// about the existence of the channel.
 	///
 	/// Note that through [`internal_closing_signed`], this function is called without the
 	/// `peer_state`  corresponding to the channel's counterparty locked, as the channel been