fixup: Add method to derive Peer Storage encryption key

Co-authored-by: Matt Corallo <[email protected]>

Author: adi2011

lightning/src/sign/mod.rs

@@ -831,10 +831,7 @@ pub trait NodeSigner {
 
 	/// Defines a method to derive a 32-byte encryption key for peer storage.
 	///
-	/// Implementations of this method must derive a secure encryption key using a
-	/// cryptographically strong key derivation function (e.g., HKDF or a hardened
-	/// child key derivation as defined in
-	/// [BIP32](https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki)).
+	/// Implementations of this method must derive a secure encryption key.
 	/// The derived key is used to encrypt or decrypt peer
 	/// storage data, ensuring confidentiality and integrity.
 	///