[test] introduce broken format that should fail prettier ci

Author: eps1lon

packages/material-ui/src/AppBar/AppBar.d.ts

@@ -4,7 +4,7 @@ import { PaperProps } from '../Paper';
 export interface AppBarProps extends StandardProps<PaperProps, AppBarClassKey> {
   color?: PropTypes.Color;
   position?: 'fixed' | 'absolute' | 'sticky' | 'static';
-}
+} 
 
 export type AppBarClassKey =
   | 'root'

packages/material-ui/src/AppBar/AppBar.js

@@ -5,7 +5,7 @@ import PropTypes from 'prop-types';
 import classNames from 'classnames';
 import withStyles from '../styles/withStyles';
 import { capitalize } from '../utils/helpers';
-import Paper from '../Paper';
+import Paper from '../Paper'; 
 
 export const styles = theme => {
   const backgroundColorDefault =