fix lint error

src/client/js/app.jsx

@@ -9,7 +9,6 @@ import ErrorBoundary from './components/ErrorBoudary';
 import SearchPage from './components/SearchPage';
 import TagsList from './components/TagsList';
 import PageEditor from './components/PageEditor';
-import PagePathNavForEditor from './components/PageEditor/PagePathNavForEditor';
 import EditorNavbarBottom from './components/PageEditor/EditorNavbarBottom';
 import { defaultEditorOptions, defaultPreviewOptions } from './components/PageEditor/OptionsSelector';
 import PageEditorByHackmd from './components/PageEditorByHackmd';