f more doc tweaks

Author: TheBlueMatt

lightning/src/util/events.rs

@@ -156,12 +156,14 @@ pub enum Event {
 		/// The fee, in milli-satoshis, which was earned as a result of the payment.
 		///
 		/// Note that if we force-closed the channel over which we forwarded an HTLC while the HTLC
-		/// was pending, the amount the next hop claimed may have been rounded down, causing a
-		/// higher fee than expected. In this case, `claim_from_onchain_tx` will be set.
+		/// was pending, the amount the next hop claimed will have been rounded down to the nearest
+		/// whole satoshi. Thus, the fee calculated here may be higher than expected as we still
+		/// claimed the full value in millisatoshis from the source. In this case,
+		/// `claim_from_onchain_tx` will be set.
 		///
 		/// If the channel which sent us the payment has been force-closed, we will claim the funds
-		/// via an on-chain transaction. In that case we do not consider the on-chain transaction
-		/// fees involved in such a claim and this value will be `None`. It is possible duplicate
+		/// via an on-chain transaction. In that case we do not yet know the on-chain transaction
+		/// fees which we will spend and will instead set this to `None`. It is possible duplicate
 		/// `PaymentForwarded` events are generated for the same payment iff `fee_earned_msat` is
 		/// `None`.
 		fee_earned_msat: Option<u64>,