如何在angular 5的ng多选下拉菜单中添加文本字段或html

<!-- app.component.html -->
<mat-form-field>
  <mat-label>选择一个或多个选项</mat-label>
  <mat-select [formControl]="selectedOptions" multiple>
    <mat-option *ngFor="let option of options" [value]="option.value">
      {{ option.label }}
      <span *ngIf="option.description" class="description">
        {{ option.description }}
      </span>
    </mat-option>
  </mat-select>
</mat-form-field>

// app.component.ts
import { Component } from '@angular/core';
import { FormControl } from '@angular/forms';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  selectedOptions = new FormControl();
  options = [
    { value: 'option1', label: '选项1', description: '这是选项1的描述' },
    { value: 'option2', label: '选项2', description: '这是选项2的描述' },
    // 更多选项...
  ];
}

/* app.component.css */
.description {
  font-size: 0.8em;
  color: #666;
}