Add new comments below older instead of the reverse (ant-design#29136)

In the example with the editor, the new comments are added on top of the older ones which is not following the way it is usually done in discussions.

components/comment/demo/editor.md

@@ -62,13 +62,13 @@ class App extends React.Component {
         submitting: false,
         value: '',
         comments: [
+          ...this.state.comments,
           {
             author: 'Han Solo',
             avatar: 'https://zos.alipayobjects.com/rmsportal/ODTLcjxAfvqbxHnVXCYX.png',
             content: <p>{this.state.value}</p>,
             datetime: moment().fromNow(),
           },
-          ...this.state.comments,
         ],
       });
     }, 1000);