refactor: clean up parser and tests (#387)

* tests: improve coverage

* refactor: clean up nodes

* chore: lint

* feat(parser): ignore `BrandVideoShelf`

Seems to be used for ads.

* feat(parser): ignore `BrandVideoSingleton` too

src/parser/classes/Alert.ts

@@ -1,7 +1,8 @@
 import Text from './misc/Text.js';
 import { YTNode } from '../helpers.js';
 import type { RawNode } from '../index.js';
-class Alert extends YTNode {
+
+export default class Alert extends YTNode {
   static type = 'Alert';
 
   text: Text;
@@ -12,6 +13,4 @@ class Alert extends YTNode {
     this.text = new Text(data.text);
     this.alert_type = data.type;
   }
-}
-
-export default Alert;
+}