refactor: Clean up & fix old code

Other changes:
- Renamed "getShortsWatchItem" to "getShortsVideoInfo".
- Fixed `ShortFormVideoInfo`. This never worked for me ever since it was introduced. Turned out it was just implemented incorrectly.
- Moved `basic_info` extraction to `MediaInfo`. Less of a pain to maintain as we only have to modify one file.
- Removed unneeded tsdoc comments.
- Fixed `Innertube#getStreamingData()`. Now it actually returns a deciphered format.
- Simplified some types.

src/parser/classes/CompactVideo.ts

@@ -13,7 +13,7 @@ export default class CompactVideo extends YTNode {
 
   id: string;
   thumbnails: Thumbnail[];
-  rich_thumbnail?: SuperParsedResult<YTNode>;
+  rich_thumbnail?: YTNode;
   title: Text;
   author: Author;
   view_count: Text;
@@ -36,7 +36,7 @@ export default class CompactVideo extends YTNode {
     this.thumbnails = Thumbnail.fromResponse(data.thumbnail) || null;
 
     if (Reflect.has(data, 'richThumbnail')) {
-      this.rich_thumbnail = Parser.parse(data.richThumbnail);
+      this.rich_thumbnail = Parser.parseItem(data.richThumbnail);
     }
 
     this.title = new Text(data.title);