Remove unused respondError function

internal/handlers/handlers.go

@@ -51,10 +51,3 @@ func (s *Handlers) respondJSON(w http.ResponseWriter, data interface{}, status i
 		}
 	}
 }
-
-func (s *Handlers) respondError(w http.ResponseWriter, code string, message string, status int) {
-	s.respondJSON(w, map[string]string{
-		"error":   code,
-		"message": message,
-	}, status)
-}