feat(Button): add icon-prefix prop (#5666)

src/grid/README.md

@@ -116,12 +116,12 @@ Vue.use(GridItem);
 |------|------|------|------|
 | text | Text | *string* | - |
 | icon | Icon name or URL | *string* | - |
+| icon-prefix `v2.5.3` | Icon className prefix | *string* | `van-icon` |
 | dot `v2.2.1` | Whether to show red dot | *boolean* | `false` |
 | info `v2.2.1` | Content of the badge | *number \| string* | - |
 | url | Link URL | *string* | - |
 | to | Target route of the link, same as to of vue-router | *string \| object* | - |
 | replace | If true, the navigation will not leave a history record | *boolean* | `false` |
-| icon-prefix `v2.5.3` | Icon className prefix | *string* | `van-icon` |
 
 ### GridItem Events
 

src/grid/README.zh-CN.md

@@ -134,12 +134,12 @@ Vue.use(GridItem);
 |------|------|------|------|
 | text | 文字 | *string* | - |
 | icon | [图标名称](#/zh-CN/icon)或图片链接 | *string* | - |
+| icon-prefix `v2.5.3` | 图标类名前缀，同 Icon 组件的 [class-prefix 属性](#/zh-CN/icon#props) | *string* | `van-icon` |
 | dot `v2.2.1` | 是否显示图标右上角小红点 | *boolean* | `false` |
 | info `v2.2.1` | 图标右上角徽标的内容 | *number \| string* | - |
 | url | 点击后跳转的链接地址 | *string* | - |
 | to | 点击后跳转的目标路由对象，同 vue-router 的 [to 属性](https://router.vuejs.org/zh/api/#to) | *string \| object* | - |
 | replace | 是否在跳转时替换当前页面历史 | *boolean* | `false` |
-| icon-prefix `v2.5.3` | 图标类名前缀 | *string* | `van-icon` |
 
 ### GridItem Events