Use generics to limit event types in on(), once() and un()

src/ol/source/UrlTile.js

@@ -33,6 +33,7 @@ import {getUid} from '../util.js';
  * Base class for sources providing tiles divided into a tile grid over http.
  *
  * @fires import("./Tile.js").TileSourceEvent
+ * @extends TileSource<'tileloadend'|'tileloaderror'|'tileloadstart'>
  */
 class UrlTile extends TileSource {
   /**