multi: rename FailUnknownPaymentHash to FailIncorrectDetails

Align naming better with the lightning spec. Not the full name of the
failure (FailIncorrectOrUnknownPaymentDetails) is used, because this
would cause too many long lines in the code.

routing/missioncontrol.go

@@ -527,7 +527,7 @@ func (m *MissionControl) applyPaymentResult(result *paymentResult) (
 	// If the end destination didn't know the payment
 	// hash or we sent the wrong payment amount to the
 	// destination, then we'll terminate immediately.
-	case *lnwire.FailUnknownPaymentHash:
+	case *lnwire.FailIncorrectDetails:
 		// TODO(joostjager): Check onionErr.Amount() whether it matches
 		// what we expect. (Will it ever not match, because if not
 		// final_incorrect_htlc_amount would be returned?)

routing/missioncontrol_store_test.go

@@ -59,7 +59,7 @@ func TestMissionControlStore(t *testing.T) {
 
 	result1 := paymentResult{
 		route:            &testRoute,
-		failure:          lnwire.NewFailUnknownPaymentHash(100),
+		failure:          lnwire.NewFailIncorrectDetails(100),
 		failureSourceIdx: &failureSourceIdx,
 		id:               99,
 		timeReply:        testTime,