vue3在使用Element-plus 2.X时，出现el-popover或el-popconfirm中button不展示问题。

正常效果：

第一种错误原因：el-button没有添加 slot='reference'

<template slot-scope="scope">
	<el-popconfirm title="您确定删除吗？" @onConfirm="cancelOrder(scope.row.id)">
	    <el-button >删除</el-button>
	</el-popconfirm>
</template>

第二种错误方式： 添加 slot='reference'  还是不展示，没想到吧！！！！！2.3.9官网就是这么写的啊

<el-popover
        placement="top"
        width="200"
        v-model="scope.row.visible">
    <p>确定删除吗？</p>
    <div style="text-align: right; margin: 0">
        <el-button type="text" @click="scope.row.visible= false">取消</el-button>
        <el-button type="text" @click="delete(scope.row.id)">确定</el-button>
    </div>
    <el-button slot="reference">删除</el-button>
</el-popover>

正确方式：

<el-popover
        placement="top"
        width="200"
        v-model="scope.row.visible">
    <p>确定删除吗？</p>
    <div style="text-align: right; margin: 0">
        <el-button type="text" @click="scope.row.visible= false">取消</el-button>
        <el-button type="text" @click="delete(scope.row.id)">确定</el-button>
    </div>
    <template #reference>
        <el-button >删除</el-button>
    </template>
</el-popover>