input框里加小圖標

<el-autocomplete
     popper-class="separator-autocomplete"
     v-model="state"
     :fetch-suggestions="querySearch"
     placeholder="搜索"
     @select="search"
     class="table-head-search"
   >
   <img src="../../images/new-search.png" slot="prepend">
</el-autocomplete>