Merge pull request #4252 from carlaKC/4226-followups

Minor followups for 4226

Author: valentinewallace

lightning/src/ln/onion_payment.rs

@@ -649,7 +649,7 @@ where
 			) {
 				Ok((amt, cltv)) => (amt, cltv),
 				Err(()) => {
-					return encode_relay_error("Trampoline blinded forward amt or CLTV values exceeded the outer onion's",
+					return encode_relay_error("Underflow calculating outbound amount or cltv value for blinded trampoline forward",
 						LocalHTLCFailureReason::InvalidOnionBlinding, outer_shared_secret.secret_bytes(), Some(trampoline_shared_secret.secret_bytes()), &[0; 32]);
 				}
 			};

lightning/src/ln/onion_utils.rs

@@ -1800,6 +1800,9 @@ impl_from_u16_for_htlc_reason!(
 		InvalidOnionPayload,
 		MPPTimeout,
 		InvalidOnionBlinding,
+		TemporaryTrampolineFailure,
+		TrampolineFeeOrExpiryInsufficient,
+		UnknownNextTrampoline,
 	]
 );