message: another dom-test-kit readme fix
diff: import { StylableDOMUtil } from '@stylable/dom-test-kit';
  import style from './my-component.st.css';
  -const domUtil = new StylableDOMUtil(style);
  +const domUtil = new StylableDOMUtil(style, document.body);
  const partElement = domUtil.select('.part');
  domUtil.hasStyleState(partElement, 'loading');
  