title: How to mark a component selector as deprecated?
body: <p>I have a component</p>
  
  <pre><code>@Component({
    // todo the app-old-selector selector must be removed in the next version
    selector: 'app-new-selector,app-old-selector',
    templateUrl: './component.html'
  })
  export class Component {
  }
  </code></pre>
  
  <p>What is the best way to inform a developer that <code>app-old-selector</code> is deprecated?</p>