fix group.md eslint

components/checkbox/demo/group.md

@@ -8,13 +8,13 @@ checkbox 组。
 
 ````jsx
 import { Checkbox } from 'antd';
-const CheckboxGroup = Checkbox.Group
+const CheckboxGroup = Checkbox.Group;
 
 function onChange(checkedValues) {
   console.log('checked = ', checkedValues);
 }
 
 ReactDOM.render(<label>
-  <CheckboxGroup options={['apple','pear']}onChange={onChange} />
+  <CheckboxGroup options={["apple", "pear"]}onChange={onChange} />
 </label>, document.getElementById('components-checkbox-demo-group'));
 ````