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/switch_test.go

@@ -1803,7 +1803,7 @@ func TestSwitchSendPayment(t *testing.T) {
 	// the add htlc request with error and sent the htlc fail request
 	// back. This request should be forwarded back to alice channel link.
 	obfuscator := NewMockObfuscator()
-	failure := lnwire.NewFailUnknownPaymentHash(update.Amount)
+	failure := lnwire.NewFailIncorrectDetails(update.Amount)
 	reason, err := obfuscator.EncryptFirstHop(failure)
 	if err != nil {
 		t.Fatalf("unable obfuscate failure: %v", err)
@@ -1824,8 +1824,9 @@ func TestSwitchSendPayment(t *testing.T) {
 
 	select {
 	case err := <-errChan:
-		assertFailureCode(t, err, lnwire.CodeUnknownPaymentHash)
-
+		assertFailureCode(
+			t, err, lnwire.CodeIncorrectOrUnknownPaymentDetails,
+		)
 	case <-time.After(time.Second):
 		t.Fatal("err wasn't received")
 	}