message: docs: fix interval type in the example
  `window.setInterval` returns a `number`, let's fix this example.
  PR Close
diff: @@ -21,7 +21,7 @@ export class AdBannerComponent implements OnInit, OnDestroy {
  @Input() ads: AdItem[] = [];
  currentAdIndex = -1;
  @ViewChild(AdDirective, {static: true}) adHost!: AdDirective;
  - interval: any;
  + interval: number | undefined;
  constructor(private componentFactoryResolver: ComponentFactoryResolver) { }
  