Change description of get_node_secret()

Author: danielgranhao

lightning/src/chain/keysinterface.rs

@@ -397,7 +397,9 @@ pub trait KeysInterface {
 	/// A type which implements Sign which will be returned by get_channel_signer.
 	type Signer : Sign;
 
-	/// Get node secret key (aka node_id or network_key) based on the provided [`Recipient`].
+	/// Get node secret key based on the provided [`Recipient`].
+	///
+	/// The node_id/network_key is the public key that corresponds to this secret key.
 	///
 	/// This method must return the same value each time it is called with a given `Recipient`
 	/// parameter.