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.

lnwire/onion_error_test.go

@@ -36,7 +36,7 @@ var onionFailures = []FailureMessage{
 	&FailIncorrectPaymentAmount{},
 	&FailFinalExpiryTooSoon{},
 
-	NewFailUnknownPaymentHash(99),
+	NewFailIncorrectDetails(99),
 	NewInvalidOnionVersion(testOnionHash),
 	NewInvalidOnionHmac(testOnionHash),
 	NewInvalidOnionKey(testOnionHash),
@@ -168,16 +168,16 @@ func TestWriteOnionErrorChanUpdate(t *testing.T) {
 	}
 }
 
-// TestFailUnknownPaymentHashOptionalAmount tests that we're able to decode an
-// UnknownPaymentHash error that doesn't have the optional amount. This ensures
-// we're able to decode FailUnknownPaymentHash messages from older nodes.
-func TestFailUnknownPaymentHashOptionalAmount(t *testing.T) {
+// TestFailIncorrectDetailsOptionalAmount tests that we're able to decode an
+// FailIncorrectDetails error that doesn't have the optional amount. This
+// ensures we're able to decode FailIncorrectDetails messages from older nodes.
+func TestFailIncorrectDetailsOptionalAmount(t *testing.T) {
 	t.Parallel()
 
 	// Creation an error that is a non-pointer will allow us to skip the
 	// type assertion for the Serializable interface. As a result, the
 	// amount body won't be written.
-	onionError := &FailUnknownPaymentHash{}
+	onionError := &FailIncorrectDetails{}
 
 	var b bytes.Buffer
 	if err := EncodeFailure(&b, onionError, 0); err != nil {