f - move docs

Author: jkczyz

lightning/src/offers/invoice.rs

@@ -425,7 +425,6 @@ impl UnsignedBolt12Invoice {
 	}
 }
 
-// Allows passing a function that takes `UnsignedBolt12Invoice` to `merkle::sign_message`.
 impl AsRef<TaggedHash> for UnsignedBolt12Invoice {
 	fn as_ref(&self) -> &TaggedHash {
 		&self.tagged_hash

lightning/src/offers/invoice_request.rs

@@ -391,7 +391,6 @@ impl UnsignedInvoiceRequest {
 	}
 }
 
-// Allows passing a function that takes `UnsignedInvoiceRequest` to `merkle::sign_message`.
 impl AsRef<TaggedHash> for UnsignedInvoiceRequest {
 	fn as_ref(&self) -> &TaggedHash {
 		&self.tagged_hash

lightning/src/offers/merkle.rs

@@ -63,6 +63,13 @@ pub enum SignError<E> {
 
 /// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream, checking if it
 /// can be verified with the supplied `pubkey`.
+///
+/// Since `message` is any type that implements [`AsRef<TaggedHash>`], `sign` may be a closure that
+/// takes a message such as [`Bolt12Invoice`] or [`InvoiceRequest`]. This allows further message
+/// verification before signing its [`TaggedHash`].
+///
+/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
+/// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 pub(super) fn sign_message<F, E, T>(
 	sign: F, message: &T, pubkey: PublicKey,
 ) -> Result<Signature, SignError<E>>