docs(Swipe): add lazy-render demo

src/swipe/README.md

@@ -36,25 +36,19 @@ Use `autoplay` prop to set autoplay interval.
 </style>
 ```
 
-### Image Lazyload
+### Lazy Render
 
-Use [Lazyload](#/en-US/lazyload) component to lazyload image.
+Use `lazy-render` prop to enable lazy rendering.
 
 ```html
-<van-swipe>
-  <van-swipe-item v-for="(image, index) in images" :key="index">
-    <img v-lazy="image" />
+<van-swipe :autoplay="3000" lazy-render>
+  <van-swipe-item v-for="image in images" :key="image">
+    <img :src="image" />
   </van-swipe-item>
 </van-swipe>
 ```
 
 ```js
-import { createApp } from 'vue';
-import { Lazyload } from 'vant';
-
-const app = createApp();
-app.use(Lazyload);
-
 export default {
   data() {
     return {