Correct name of get_counterparty_payment_script method

`get_counterparty_payment_script` fetches the countersigner's (i.e.
non-broadcaster) payment script, but that could be ours or or
counterparty's. Thus, it should read
`get_countersigner_payment_script`, which we fix here.

Author: TheBlueMatt

lightning/src/chain/channelmonitor.rs

@@ -1857,7 +1857,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitor<Signer> {
 
 		assert!(commitment_transaction_number_obscure_factor <= (1 << 48));
 		let holder_pubkeys = &channel_parameters.holder_pubkeys;
-		let counterparty_payment_script = chan_utils::get_counterparty_payment_script(
+		let counterparty_payment_script = chan_utils::get_countersigner_payment_script(
 			&channel_parameters.channel_type_features, &holder_pubkeys.payment_point
 		);
 

lightning/src/ln/chan_utils.rs

@@ -637,9 +637,9 @@ pub fn get_revokeable_redeemscript(revocation_key: &RevocationKey, contest_delay
 	res
 }
 
-/// Returns the script for the counterparty's output on a holder's commitment transaction based on
-/// the channel type.
-pub fn get_counterparty_payment_script(
+/// Returns the script for the countersigner's (i.e. non-broadcaster's) output on a commitment
+/// transaction based on the channel type.
+pub fn get_countersigner_payment_script(
 	channel_type_features: &ChannelTypeFeatures, payment_key: &PublicKey,
 ) -> ScriptBuf {
 	if channel_type_features.supports_anchors_zero_fee_htlc_tx() {

lightning/src/sign/mod.rs

@@ -41,7 +41,7 @@ use crate::chain::transaction::OutPoint;
 use crate::crypto::utils::{hkdf_extract_expand_twice, sign, sign_with_aux_rand};
 use crate::ln::chan_utils;
 use crate::ln::chan_utils::{
-	get_counterparty_payment_script, get_revokeable_redeemscript, make_funding_redeemscript,
+	get_countersigner_payment_script, get_revokeable_redeemscript, make_funding_redeemscript,
 	ChannelPublicKeys, ChannelTransactionParameters, ClosingTransaction, CommitmentTransaction,
 	HTLCOutputInCommitment, HolderCommitmentTransaction,
 };
@@ -1295,8 +1295,8 @@ impl InMemorySigner {
 
 		let payment_point_v1 = PublicKey::from_secret_key(secp_ctx, &self.payment_key_v1);
 		let payment_point_v2 = PublicKey::from_secret_key(secp_ctx, &self.payment_key_v2);
-		let spk_v1 = get_counterparty_payment_script(channel_type_features, &payment_point_v1);
-		let spk_v2 = get_counterparty_payment_script(channel_type_features, &payment_point_v2);
+		let spk_v1 = get_countersigner_payment_script(channel_type_features, &payment_point_v1);
+		let spk_v2 = get_countersigner_payment_script(channel_type_features, &payment_point_v2);
 
 		let (remotepubkey, payment_key) = if spk_v1 == descriptor.output.script_pubkey {
 			(bitcoin::PublicKey::new(payment_point_v1), &self.payment_key_v1)
@@ -2075,7 +2075,12 @@ impl KeysManager {
 	}
 
 	/// Gets the set of possible `script_pubkey`s which can appear on chain for our
-	/// non-HTLC-encumbered balance if our counterparty force-closes the channel.
+	/// non-HTLC-encumbered balance if our counterparty force-closes a channel.
+	///
+	/// If you've lost all data except your seed, asking your peers nicely to force-close the
+	/// chanels they had with you (and hoping they don't broadcast a stale state and that there are
+	/// no pending HTLCs in the latest state) and scanning the chain for these `script_pubkey`s can
+	/// allow you to recover (some of) your funds.
 	///
 	/// Only channels opened when using a [`KeysManager`] with the `v2_remote_key_derivation`
 	/// argument to [`KeysManager::new`] set, or any spliced channels will close to such scripts,
@@ -2097,8 +2102,8 @@ impl KeysManager {
 				.expect("Your RNG is busted")
 				.private_key;
 			let pubkey = PublicKey::from_secret_key(secp_ctx, &key);
-			res.push(get_counterparty_payment_script(&static_remote_key_features, &pubkey));
-			res.push(get_counterparty_payment_script(&zero_fee_htlc_features, &pubkey));
+			res.push(get_countersigner_payment_script(&static_remote_key_features, &pubkey));
+			res.push(get_countersigner_payment_script(&zero_fee_htlc_features, &pubkey));
 		}
 		res
 	}