f clarify what we're doing

Author: TheBlueMatt

fuzz/src/chanmon_consistency.rs

@@ -718,7 +718,8 @@ pub fn do_test<Out: Output>(data: &[u8], underlying_out: Out, anchors: bool) {
 					let old_mon = prev_state.persisted_monitor;
 					prev_state.pending_monitors.pop().map(|(_, v)| v).unwrap_or(old_mon)
 				};
-				// Use a different value of `use_old_mons` if we have another monitor (only node B)
+				// Use a different value of `use_old_mons` if we have another monitor (only for
+				// node B) by shifting `use_old_mons` one in base-3.
 				use_old_mons /= 3;
 				let mon = <(BlockHash, ChannelMonitor<TestChannelSigner>)>::read(
 					&mut &serialized_mon[..],