Rename PaymentSendFailure::AllFailedRetrySafe ...ResendSafe

It was pointed out that its quite confusing that
`AllFailedRetrySafe` does not allow you to call `retry_payment`,
though the documentation on it does specify this. Instead, we
simply rename it to `AllFailedResendSafe` to indicate that the
action that is safe to take is *resending*, not *retrying*.

Author: TheBlueMatt

lightning/src/ln/channelmanager.rs

@@ -1203,9 +1203,10 @@ pub enum PaymentSendFailure {
 	/// You can freely retry the payment in full (though you probably want to do so over different
 	/// paths than the ones selected).
 	///
-	/// [`ChannelManager::abandon_payment`] does *not* need to be called for this payment and
-	/// [`ChannelManager::retry_payment`] will *not* work for this payment.
-	AllFailedRetrySafe(Vec<APIError>),
+	/// Because the payment failed outright, no payment tracking is done, you do not need to call
+	/// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
+	/// for this payment.
+	AllFailedResendSafe(Vec<APIError>),
 	/// Some paths which were attempted failed to send, though possibly not all. At least some
 	/// paths have irrevocably committed to the HTLC and retrying the payment in full would result
 	/// in over-/re-payment.
@@ -2707,7 +2708,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 			// `pending_outbound_payments` map, as the user isn't expected to `abandon_payment`.
 			let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
 			debug_assert!(removed, "We should always have a pending payment to remove here");
-			Err(PaymentSendFailure::AllFailedRetrySafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
+			Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
 		} else {
 			Ok(())
 		}

lightning/src/ln/functional_test_utils.rs

@@ -587,7 +587,7 @@ macro_rules! get_local_commitment_txn {
 macro_rules! unwrap_send_err {
 	($res: expr, $all_failed: expr, $type: pat, $check: expr) => {
 		match &$res {
-			&Err(PaymentSendFailure::AllFailedRetrySafe(ref fails)) if $all_failed => {
+			&Err(PaymentSendFailure::AllFailedResendSafe(ref fails)) if $all_failed => {
 				assert_eq!(fails.len(), 1);
 				match fails[0] {
 					$type => { $check },

lightning/src/ln/functional_tests.rs

@@ -1332,7 +1332,7 @@ fn test_basic_channel_reserve() {
 	let (route, our_payment_hash, _, our_payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1], max_can_send + 1);
 	let err = nodes[0].node.send_payment(&route, our_payment_hash, &Some(our_payment_secret), PaymentId(our_payment_hash.0)).err().unwrap();
 	match err {
-		PaymentSendFailure::AllFailedRetrySafe(ref fails) => {
+		PaymentSendFailure::AllFailedResendSafe(ref fails) => {
 			match &fails[0] {
 				&APIError::ChannelUnavailable{ref err} =>
 					assert!(regex::Regex::new(r"Cannot send value that would put our balance under counterparty-announced channel reserve value \(\d+\)").unwrap().is_match(err)),