f better docs on chanman read/init

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -12217,10 +12217,11 @@ impl Readable for VecDeque<(Event, Option<EventCompletionAction>)> {
 /// 3) If you are not fetching full blocks, register all relevant [`ChannelMonitor`] outpoints the
 ///    same way you would handle a [`chain::Filter`] call using
 ///    [`ChannelMonitor::get_outputs_to_watch`] and [`ChannelMonitor::get_funding_txo`].
-/// 4) Reconnect blocks on your [`ChannelMonitor`]s.
-/// 5) Disconnect/connect blocks on the [`ChannelManager`].
+/// 4) Disconnect/connect blocks on your [`ChannelMonitor`]s to get them in sync with the chain.
+/// 5) Disconnect/connect blocks on the [`ChannelManager`] to get it in sync with the chain.
 /// 6) Optionally re-persist the [`ChannelMonitor`]s to ensure the latest state is on disk.
-///    This is important if you have replayed a nontrivial number of blocks in step (4) but is
+///    This is important if you have replayed a nontrivial number of blocks in step (4), allowing
+///    you to avoid having to replay the same blocks if you shut down quickly after startup. It is
 ///    otherwise not required.
 ///    Note that if you're using a [`ChainMonitor`] for your [`chain::Watch`] implementation, you
 ///    will likely accomplish this as a side-effect of calling [`chain::Watch::watch_channel`] in