multi: update linter, fix new issues

htlcswitch/failure_test.go

@@ -19,9 +19,9 @@ func TestLongFailureMessage(t *testing.T) {
 	t.Parallel()
 
 	var testData struct {
-		SessionKey string
-		Path       []string
-		Reason     string
+		SessionKey string   `json:"session_key"`
+		Path       []string `json:"path"`
+		Reason     string   `json:"reason"`
 	}
 
 	// Use long 1024-byte test vector from BOLT 04.

htlcswitch/mock.go

@@ -1102,7 +1102,7 @@ func (m *mockOnionErrorDecryptor) DecryptError(encryptedData []byte) (
 var _ htlcNotifier = (*mockHTLCNotifier)(nil)
 
 type mockHTLCNotifier struct {
-	htlcNotifier
+	htlcNotifier //nolint:unused
 }
 
 func (h *mockHTLCNotifier) NotifyForwardingEvent(key HtlcKey, info HtlcInfo,

htlcswitch/testdata/long_failure_msg.json

@@ -1,5 +1,5 @@
 {
-	"sessionKey": "4141414141414141414141414141414141414141414141414141414141414141",
+	"session_key": "4141414141414141414141414141414141414141414141414141414141414141",
 	"path": [
 		"02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619",
 		"0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c",