Improve comment around dust exposure

Author: ariard

lightning/src/util/config.rs

@@ -320,10 +320,13 @@ impl Default for ChannelHandshakeLimits {
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum MaxDustHTLCExposure {
 	/// This sets a fixed limit on the total dust exposure in millisatoshis. Setting this too low
-	/// may prevent the sending or receipt of low-value HTLCs on high-traffic nodes, however this
-	/// limit is very important to prevent stealing of large amounts of dust HTLCs by miners
-	/// through [fee griefing
-	/// attacks](https://lists.linuxfoundation.org/pipermail/lightning-dev/2020-May/002714.html).
+	/// may prevent the sending or receipt of low-value HTLCs on high-traffic nodes. However this
+	/// limit is very important to prevent two types of risks:
+	/// - dust HTLCs balance stealing by Lightning counterparties with hashrate capabilities
+	/// - fee griefing attacks by colluding Lightning counterparties on the routing of HTLC without _hashrate_ capabilities
+	///
+	/// For more information see ["dust inflation attacks"](https://lists.linuxfoundation.org/pipermail/lightning-dev/2020-May/002714.html)
+	/// and ["dust HTLC exposure considered harmful"](https://lists.linuxfoundation.org/pipermail/lightning-dev/2020-May/002714.html).
 	///
 	/// Note that if the feerate increases significantly, without a manually increase
 	/// to this maximum the channel may be unable to send/receive HTLCs between the maximum dust