Add logging in route hint filtering

Knowing why a channel was not included as an invoice route hint can be
valuable. Add logging on the decisions made when filtering channels.

Author: jkczyz

lightning-invoice/src/payment.rs

@@ -2199,8 +2199,8 @@ mod tests {
 		let invoice_payer = InvoicePayer::new(nodes[0].node, router, nodes[0].logger, event_handler, Retry::Attempts(1));
 
 		assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
-			&nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string(),
-			duration_since_epoch(), 3600).unwrap())
+			&nodes[1].node, nodes[1].keys_manager, nodes[0].logger, Currency::Bitcoin,
+			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600).unwrap())
 			.is_ok());
 		let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(htlc_msgs.len(), 2);
@@ -2244,8 +2244,8 @@ mod tests {
 		let invoice_payer = InvoicePayer::new(nodes[0].node, router, nodes[0].logger, event_handler, Retry::Attempts(1));
 
 		assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
-			&nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string(),
-			duration_since_epoch(), 3600).unwrap())
+			&nodes[1].node, nodes[1].keys_manager, nodes[0].logger, Currency::Bitcoin,
+			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600).unwrap())
 			.is_ok());
 		let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(htlc_msgs.len(), 2);
@@ -2325,8 +2325,8 @@ mod tests {
 		let invoice_payer = InvoicePayer::new(nodes[0].node, router, nodes[0].logger, event_handler, Retry::Attempts(1));
 
 		assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
-			&nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string(),
-			duration_since_epoch(), 3600).unwrap())
+			&nodes[1].node, nodes[1].keys_manager, nodes[0].logger, Currency::Bitcoin,
+			Some(100_010_000), "Invoice".to_string(), duration_since_epoch(), 3600).unwrap())
 			.is_ok());
 		let htlc_updates = SendEvent::from_node(&nodes[0]);
 		check_added_monitors!(nodes[0], 1);