title: how to add a secondary action in mat-list-option (mat-selection-list) item
body: <p>How is it possible, to add an secondary action (mat-icon-button) in an mat-selection-list inside the mat-list-option element.</p>
  
  <p>Currently all items are added inside the mat-list-text div.</p>
  
  <p><strong>example (<a href="https://stackblitz.com/edit/angular-dwac7y" rel="noreferrer">https://stackblitz.com/edit/angular-dwac7y</a>):</strong></p>
  
  <pre><code>&lt;mat-selection-list [(ngModel)]="selectedOptions"&gt;
      &lt;mat-list-option *ngFor="let item of items;" [value]="item.id" [disableRipple]="true"&gt;
          &lt;mat-icon matListAvatar&gt;person&lt;/mat-icon&gt;
  
          &lt;h3 matLine&gt; {{item.name}}&lt;/h3&gt;
          &lt;p matLine&gt;
              {{item.details}}
          &lt;/p&gt;
  
          &lt;button mat-icon-button (click)="onEdit($event, item)"&gt;
              &lt;mat-icon&gt;edit&lt;/mat-icon&gt;
          &lt;/button&gt;
      &lt;/mat-list-option&gt;
  &lt;/mat-selection-list&gt;
  </code></pre>