extensions/markdown-language-features/src/markdownEngine.ts/MdParsingProvider/constructor
class MdParsingProvider:	constructor(
		engine: MarkdownItEngine,
		workspace: IMdWorkspace,
	) {
		super();

		this.slugifier = engine.slugifier;

		this._cache = this._register(new MdDocumentInfoCache<Token[]>(workspace, doc => {
			return engine.tokenize(doc);
		}));
	}