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.

htlcswitch/link_test.go

@@ -623,7 +623,7 @@ func TestExitNodeAmountPayloadMismatch(t *testing.T) {
 	if err == nil {
 		t.Fatalf("payment should have failed but didn't")
 	}
-	assertFailureCode(t, err, lnwire.CodeUnknownPaymentHash)
+	assertFailureCode(t, err, lnwire.CodeIncorrectOrUnknownPaymentDetails)
 }
 
 // TestLinkForwardTimelockPolicyMismatch tests that if a node is an
@@ -1130,7 +1130,9 @@ func TestChannelLinkMultiHopUnknownPaymentHash(t *testing.T) {
 		t.Fatalf("no result arrive")
 	}
 
-	assertFailureCode(t, result.Error, lnwire.CodeUnknownPaymentHash)
+	assertFailureCode(
+		t, result.Error, lnwire.CodeIncorrectOrUnknownPaymentDetails,
+	)
 
 	// Wait for Alice to receive the revocation.
 	time.Sleep(100 * time.Millisecond)
@@ -5668,7 +5670,7 @@ func TestChannelLinkCanceledInvoice(t *testing.T) {
 	if !ok {
 		t.Fatalf("expected ForwardingError, but got %v", err)
 	}
-	_, ok = fErr.FailureMessage.(*lnwire.FailUnknownPaymentHash)
+	_, ok = fErr.FailureMessage.(*lnwire.FailIncorrectDetails)
 	if !ok {
 		t.Fatalf("expected unknown payment hash, but got %v", err)
 	}
@@ -5837,7 +5839,7 @@ func TestChannelLinkHoldInvoiceCancel(t *testing.T) {
 
 	// Wait for payment to succeed.
 	err = <-ctx.errChan
-	assertFailureCode(t, err, lnwire.CodeUnknownPaymentHash)
+	assertFailureCode(t, err, lnwire.CodeIncorrectOrUnknownPaymentDetails)
 }
 
 // TestChannelLinkHoldInvoiceRestart asserts hodl htlcs are held after blocks