WIP: Expand ChannelManager documentation

Author: jkczyz

lightning/src/ln/channelmanager.rs

@@ -974,6 +974,26 @@ where
 /// Additionally, [`ChannelManager`] implements both [`chain::Listen`] and [`chain::Confirm`] for
 /// notification of on-chain events.
 ///
+/// # `ChannelManager` vs `ChainMonitor`
+///
+///	TODO
+///
+/// # Initialization
+///
+///	TODO
+///
+/// # Operation
+///
+///	TODO
+///	- event processing
+///	- timer ticks
+///	- chain data
+///	- persistence
+///
+/// # Payments
+///
+/// TODO
+///
 /// # Persistence
 ///
 /// Implements [`Writeable`] to write out all channel state to disk. Implies [`peer_disconnected`] for