Rename claim cleaning match bool for accuracy

We don't actually care if a confirmed transaction claimed other
outputs, only that it claimed a superset of the outputs in the
pending claim we're looking at. Thus, the variable to detect that
is renamed `is_claim_subset_of_tx` instead of `are_sets_equal`.

Author: TheBlueMatt

lightning/src/chain/onchaintx.rs

@@ -885,15 +885,16 @@ impl<ChannelSigner: EcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 				if let Some((claim_id, _)) = self.claimable_outpoints.get(&inp.previous_output) {
 					// If outpoint has claim request pending on it...
 					if let Some(request) = self.pending_claim_requests.get_mut(claim_id) {
-						//... we need to verify equality between transaction outpoints and claim request
-						// outpoints to know if transaction is the original claim or a bumped one issued
-						// by us.
-						let mut are_sets_equal = true;
+						//... we need to check if the pending claim was for a subset of the outputs
+						// spent by the confirmed transaction. If so, we can drop the pending claim
+						// after ANTI_REORG_DELAY blocks, otherwise we need to split it and retry
+						// claiming the remaining outputs.
+						let mut is_claim_subset_of_tx = true;
 						let mut tx_inputs = tx.input.iter().map(|input| &input.previous_output).collect::<Vec<_>>();
 						tx_inputs.sort_unstable();
 						for request_input in request.outpoints() {
 							if tx_inputs.binary_search(&request_input).is_err() {
-								are_sets_equal = false;
+								is_claim_subset_of_tx = false;
 								break;
 							}
 						}
@@ -915,7 +916,7 @@ impl<ChannelSigner: EcdsaChannelSigner> OnchainTxHandler<ChannelSigner> {
 						// If this is our transaction (or our counterparty spent all the outputs
 						// before we could anyway with same inputs order than us), wait for
 						// ANTI_REORG_DELAY and clean the RBF tracking map.
-						if are_sets_equal {
+						if is_claim_subset_of_tx {
 							clean_claim_request_after_safety_delay!();
 						} else { // If false, generate new claim request with update outpoint set
 							let mut at_least_one_drop = false;