docs(BackTop): add click event document (#11514)

packages/vant/docs/markdown/home.en-US.md

@@ -98,4 +98,4 @@ Please make sure to read the [Contributing Guide](https://github.com/vant-ui/van
 
 ### LICENSE
 
-[MIT](https://zh.wikipedia.org/wiki/MIT%E8%A8%B1%E5%8F%AF%E8%AD%89)
+[MIT](https://zh.wikipedia.org/wiki/MIT%E8%A8%B1%E5%8F%AF%E8%AD%89).

packages/vant/docs/markdown/home.zh-CN.md

@@ -115,4 +115,4 @@ Vant 3/4 支持现代浏览器以及 Chrome >= 51、iOS >= 10.0（与 Vue 3 一
 
 ### 开源协议
 
-本项目基于 [MIT](https://zh.wikipedia.org/wiki/MIT%E8%A8%B1%E5%8F%AF%E8%AD%89) 协议，请自由地享受和参与开源
+本项目基于 [MIT](https://zh.wikipedia.org/wiki/MIT%E8%A8%B1%E5%8F%AF%E8%AD%89) 协议，请自由地享受和参与开源。

packages/vant/src/back-top/README.md

@@ -116,6 +116,12 @@ export default {
 | offset | The component will not display until the scroll offset reaches this value | _number_ | `200` |
 | teleport | Specifies a target element where BackTop will be mounted | _string \| Element_ | `body` |
 
+### Events
+
+| Event | Description                       | Arguments           |
+| ----- | --------------------------------- | ------------------- |
+| click | Emitted when Component is clicked | _event: MouseEvent_ |
+
 ### Slots
 
 | Name    | Description               |

packages/vant/src/back-top/README.zh-CN.md

@@ -20,7 +20,7 @@ app.use(BackTop);
 
 ### 基础用法
 
-请滚动示例页面来查看右下角的返回顶部按钮。
+请滚动右侧的示例页面，当页面滚动 `200px` 时，右下角会出现返回顶部按钮。
 
 ```html
 <van-cell v-for="item in list" :key="item" :title="item" /> <van-back-top />
@@ -118,6 +118,12 @@ export default {
 | offset | 滚动高度达到此参数值时才显示组件 | _number_ | `200` |
 | teleport | 指定挂载的节点，等同于 Teleport 组件的 [to 属性](https://v3.cn.vuejs.org/api/built-in-components.html#teleport) | _string \| Element_ | `body` |
 
+### Events
+
+| 事件  | 说明           | 回调参数            |
+| ----- | -------------- | ------------------- |
+| click | 点击组件时触发 | _event: MouseEvent_ |
+
 ### Slots
 
 | 名称    | 说明               |

packages/vant/src/back-top/demo/index.vue

@@ -27,7 +27,7 @@ const targetEl = ref<HTMLElement>();
 </script>
 
 <template>
-  <van-tabs v-model:active="activeTab">
+  <van-tabs v-model:active="activeTab" :ellipsis="false">
     <van-tab :title="t('basicUsage')">
       <van-cell v-for="item in list" :key="item" :title="item" />
       <van-back-top v-if="activeTab === 0" />

packages/vant/src/back-top/test/__snapshots__/demo.spec.ts.snap

@@ -4,50 +4,50 @@ exports[`should render demo and match snapshot 1`] = `
 <div class="van-tabs van-tabs--line">
   <div class="van-tabs__wrap">
     <div role="tablist"
-         class="van-tabs__nav van-tabs__nav--line"
+         class="van-tabs__nav van-tabs__nav--line van-tabs__nav--complete"
          aria-orientation="horizontal"
     >
       <div id="van-tabs-0"
            role="tab"
-           class="van-tab van-tab--line van-tab--active"
+           class="van-tab van-tab--line van-tab--grow van-tab--active"
            tabindex="0"
            aria-selected="true"
            aria-controls="van-tab"
       >
-        <span class="van-tab__text van-tab__text--ellipsis">
+        <span class="van-tab__text">
           Basic Usage
         </span>
       </div>
       <div id="van-tabs-1"
            role="tab"
-           class="van-tab van-tab--line"
+           class="van-tab van-tab--line van-tab--grow"
            tabindex="-1"
            aria-selected="false"
            aria-controls="van-tab"
       >
-        <span class="van-tab__text van-tab__text--ellipsis">
+        <span class="van-tab__text">
           Custom Position
         </span>
       </div>
       <div id="van-tabs-2"
            role="tab"
-           class="van-tab van-tab--line"
+           class="van-tab van-tab--line van-tab--grow"
            tabindex="-1"
            aria-selected="false"
            aria-controls="van-tab"
       >
-        <span class="van-tab__text van-tab__text--ellipsis">
+        <span class="van-tab__text">
           Custom Content
         </span>
       </div>
       <div id="van-tabs-3"
            role="tab"
-           class="van-tab van-tab--line"
+           class="van-tab van-tab--line van-tab--grow"
            tabindex="-1"
            aria-selected="false"
            aria-controls="van-tab"
       >
-        <span class="van-tab__text van-tab__text--ellipsis">
+        <span class="van-tab__text">
           Set Scroll Target
         </span>
       </div>