doc: demo translation enhancement (#3033)

* doc enhancement

* keep chinese simplified demo

components/badge/demo/change.md

@@ -59,7 +59,7 @@ const Test = React.createClass({
             </Button>
           </ButtonGroup>
           <Button type="ghost" onClick={this.onClick} style={{ marginLeft: 8 }}>
-            Red badge toggle
+            Switch state
           </Button>
         </div>
       </div>

components/badge/demo/dot.md

@@ -21,7 +21,7 @@ ReactDOM.render(<div>
     <Icon type="notification" />
   </Badge>
   <Badge dot>
-    <a href="#">A Link</a>
+    <a href="#">Link something</a>
   </Badge>
 </div>, mountNode);
 ````

components/form/demo/form-in-modal.md

@@ -45,7 +45,7 @@ let Demo = React.createClass({
     };
     return (
       <div>
-        <Button type="primary" onClick={this.showModal}>点击有惊喜</Button>
+        <Button type="primary" onClick={this.showModal}>Surprise</Button>
         <Modal title="login" visible={this.state.visible} onOk={this.handleSubmit} onCancel={this.hideModal}>
           <Form horizontal>
             <FormItem

components/switch/demo/text.md

@@ -18,6 +18,7 @@ import { Switch, Icon } from 'antd';
 
 ReactDOM.render(<div>
   <Switch checkedChildren="开" unCheckedChildren="关" />
+  <Switch checkedChildren="On" unCheckedChildren="Off" />
   <Switch checkedChildren={<Icon type="check" />} unCheckedChildren={<Icon type="cross" />} />
 </div>, mountNode);
 ````