Extend linter rules (#1300)

- dupword checks for duplicate words in the source code
- durationcheck checks for two durations multiplied together
- forbidigo forbids identifiers
- mirror reports wrong mirror patterns of bytes/strings usage
- misspell finds commonly misspelled English words in comments
- predeclared finds code that shadows one of Go's predeclared identifiers
- thelper detects Go test helpers without t.Helper() call and checks the consistency of test helpers

management/server/route_test.go

@@ -1007,6 +1007,7 @@ func TestGetNetworkMap_RouteSync(t *testing.T) {
 }
 
 func createRouterManager(t *testing.T) (*DefaultAccountManager, error) {
+	t.Helper()
 	store, err := createRouterStore(t)
 	if err != nil {
 		return nil, err
@@ -1016,6 +1017,7 @@ func createRouterManager(t *testing.T) (*DefaultAccountManager, error) {
 }
 
 func createRouterStore(t *testing.T) (Store, error) {
+	t.Helper()
 	dataDir := t.TempDir()
 	store, err := NewStoreFromJson(dataDir, nil)
 	if err != nil {