f - update timer_tick_occurred docs

Author: jkczyz

lightning/src/ln/channelmanager.rs

@@ -4789,6 +4789,10 @@ where
 	///    with the current [`ChannelConfig`].
 	///  * Removing peers which have disconnected but and no longer have any channels.
 	///  * Force-closing and removing channels which have not completed establishment in a timely manner.
+	///  * Forgetting about stale outbound payment, either those that have already been fulfilled or
+	///    those awaiting an invoice that hasn't been delivered in the necessary amount of time. The
+	///    latter is determined using the system clock in `std` and the block time minus two hours
+	///    in `no-std`.
 	///
 	/// Note that this may cause reentrancy through [`chain::Watch::update_channel`] calls or feerate
 	/// estimate fetches.