extensions/markdown-language-features/src/preview/preview.ts/MarkdownPreview/dispose
class MarkdownPreview:	override dispose() {
		this._disposeCts.cancel();

		super.dispose();

		this._disposed = true;

		clearTimeout(this._throttleTimer);
		for (const entry of this._fileWatchersBySrc.values()) {
			entry.dispose();
		}
		this._fileWatchersBySrc.clear();
	}