Pass FailureCode to fail_htlc_backwards by ownership

`FaliureCode` is a trivial enum with no body, so we shouldn't be
passing it by reference. Its sufficiently strange that the Java
bindings aren't happy with it, which is fine, we should just fix it
here.

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -3653,14 +3653,14 @@ where
 	/// [`events::Event::PaymentClaimed`] events even for payments you intend to fail, especially on
 	/// startup during which time claims that were in-progress at shutdown may be replayed.
 	pub fn fail_htlc_backwards(&self, payment_hash: &PaymentHash) {
-		self.fail_htlc_backwards_with_reason(payment_hash, &FailureCode::IncorrectOrUnknownPaymentDetails);
+		self.fail_htlc_backwards_with_reason(payment_hash, FailureCode::IncorrectOrUnknownPaymentDetails);
 	}
 
 	/// This is a variant of [`ChannelManager::fail_htlc_backwards`] that allows you to specify the
 	/// reason for the failure.
 	///
 	/// See [`FailureCode`] for valid failure codes.
-	pub fn fail_htlc_backwards_with_reason(&self, payment_hash: &PaymentHash, failure_code: &FailureCode) {
+	pub fn fail_htlc_backwards_with_reason(&self, payment_hash: &PaymentHash, failure_code: FailureCode) {
 		let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(&self.total_consistency_lock, &self.persistence_notifier);
 
 		let removed_source = self.claimable_payments.lock().unwrap().claimable_htlcs.remove(payment_hash);
@@ -3675,14 +3675,14 @@ where
 	}
 
 	/// Gets error data to form an [`HTLCFailReason`] given a [`FailureCode`] and [`ClaimableHTLC`].
-	fn get_htlc_fail_reason_from_failure_code(&self, failure_code: &FailureCode, htlc: &ClaimableHTLC) -> HTLCFailReason {
+	fn get_htlc_fail_reason_from_failure_code(&self, failure_code: FailureCode, htlc: &ClaimableHTLC) -> HTLCFailReason {
 		match failure_code {
-			FailureCode::TemporaryNodeFailure => HTLCFailReason::from_failure_code(*failure_code as u16),
-			FailureCode::RequiredNodeFeatureMissing => HTLCFailReason::from_failure_code(*failure_code as u16),
+			FailureCode::TemporaryNodeFailure => HTLCFailReason::from_failure_code(failure_code as u16),
+			FailureCode::RequiredNodeFeatureMissing => HTLCFailReason::from_failure_code(failure_code as u16),
 			FailureCode::IncorrectOrUnknownPaymentDetails => {
 				let mut htlc_msat_height_data = htlc.value.to_be_bytes().to_vec();
 				htlc_msat_height_data.extend_from_slice(&self.best_block.read().unwrap().height().to_be_bytes());
-				HTLCFailReason::reason(*failure_code as u16, htlc_msat_height_data)
+				HTLCFailReason::reason(failure_code as u16, htlc_msat_height_data)
 			}
 		}
 	}

lightning/src/ln/onion_route_tests.rs

@@ -848,7 +848,7 @@ fn do_test_fail_htlc_backwards_with_reason(failure_code: FailureCode) {
 
 	expect_pending_htlcs_forwardable!(nodes[1]);
 	expect_payment_claimable!(nodes[1], payment_hash, payment_secret, payment_amount);
-	nodes[1].node.fail_htlc_backwards_with_reason(&payment_hash, &failure_code);
+	nodes[1].node.fail_htlc_backwards_with_reason(&payment_hash, failure_code);
 
 	expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::FailedPayment { payment_hash: payment_hash }]);
 	check_added_monitors!(nodes[1], 1);