Minor Doc fixes after lightningdevkit#2957

lightning/src/chain/chainmonitor.rs

@@ -148,7 +148,7 @@ pub trait Persist<ChannelSigner: WriteableEcdsaChannelSigner> {
 	/// The [`ChannelMonitorUpdate::update_id`] or [`ChannelMonitor::get_latest_update_id`] uniquely
 	/// links this call to [`ChainMonitor::channel_monitor_updated`].
 	/// For [`Persist::update_persisted_channel`], it is only necessary to call [`ChainMonitor::channel_monitor_updated`]
-	/// when an [`ChannelMonitorUpdate`] is provided and when you return [`ChannelMonitorUpdateStatus::InProgress`].
+	/// when a [`ChannelMonitorUpdate`] is provided and when you return [`ChannelMonitorUpdateStatus::InProgress`].
 	///
 	/// See [`Writeable::write`] on [`ChannelMonitor`] for writing out a `ChannelMonitor`,
 	/// [`Writeable::write`] on [`ChannelMonitorUpdate`] for writing out an update, and