f clarify comment

Author: TheBlueMatt

lightning/src/ln/payment_tests.rs

@@ -1310,12 +1310,13 @@ fn claimed_send_payment_idempotent() {
 	expect_payment_sent!(&nodes[0], first_payment_preimage, Some(0));
 	check_send_rejected!();
 
-	// However, after some time has passed (at least more than one timer tick), a duplicate payment
-	// should go through, as ChannelManager should no longer have any remaining references to the
-	// old payment data.
+	// If relatively little time has passed, a duplicate payment should still fail.
 	nodes[0].node.timer_tick_occurred();
 	check_send_rejected!();
 
+	// However, after some time has passed (at least more than one timer tick), a duplicate payment
+	// should go through, as ChannelManager should no longer have any remaining references to the
+	// old payment data.
 	for _ in 0..10 {
 		nodes[0].node.timer_tick_occurred();
 	}