rewrite Pagination demos to es6 component, #4878

components/pagination/demo/controlled.md

@@ -16,22 +16,20 @@ Controlled page number.
 ````jsx
 import { Pagination } from 'antd';
 
-const Container = React.createClass({
-  getInitialState() {
-    return {
-      current: 3,
-    };
-  },
-  onChange(page) {
+class App extends React.Component {
+  state = {
+    current: 3,
+  }
+  onChange = (page) => {
     console.log(page);
     this.setState({
       current: page,
     });
-  },
+  }
   render() {
     return <Pagination current={this.state.current} onChange={this.onChange} total={50} />;
-  },
-});
+  }
+}
 
-ReactDOM.render(<Container />, mountNode);
+ReactDOM.render(<App />, mountNode);
 ````