Simplify and clarify `derive_add_tweak` documentation

diff --git a/lightning/src/ln/channel_keys.rs b/lightning/src/ln/channel_keys.rs
index 423d410740720dc2bb5b4e12aa39cf5d1bf4c2ca..76dc1e42b37d72e7dca1d92c98ff7193cc817693 100644 (file)
--- a/lightning/src/ln/channel_keys.rs
+++ b/lightning/src/ln/channel_keys.rs
@@ -38,13 +38,13 @@ macro_rules! basepoint_impl {
                                self.0
                        }
 
-                       /// Derives a per-commitment-transaction (eg an htlc key or delayed_payment key) private key addition tweak
-                       /// from a basepoint and a per_commitment_point:
+                       /// Derives the "tweak" used to calculate the per-commitment private key.
+                       ///
+                       /// The per-commitment private key is calculates a private key as:
                        /// `privkey = basepoint_secret + SHA256(per_commitment_point || basepoint)`
-                       /// This calculates the hash part in the tweak derivation process, which is used to ensure
-                       /// that each key is unique and cannot be guessed by an external party. It is equivalent
-                       /// to the `from_basepoint` method, but without the addition operation, providing just the
-                       /// tweak from the hash of the per_commitment_point and the basepoint.
+                       ///
+                       /// This calculates the hash part in the tweak derivation process, which is used to
+                       /// ensure that each key is unique and cannot be guessed by an external party.
                        pub fn derive_add_tweak(&self, per_commitment_point: &PublicKey) -> [u8; 32] {
                                let mut sha = Sha256::engine();
                                sha.input(&per_commitment_point.serialize());