extensions/markdown-language-features/src/languageFeatures/folding.ts/MdFoldingProvider/provideFoldingRanges
class MdFoldingProvider:	public async provideFoldingRanges(
		document: ITextDocument,
		_: vscode.FoldingContext,
		_token: vscode.CancellationToken
	): Promise<vscode.FoldingRange[]> {
		const foldables = await Promise.all([
			this.getRegions(document),
			this.getHeaderFoldingRanges(document),
			this.getBlockFoldingRanges(document)
		]);
		return foldables.flat().slice(0, rangeLimit);
	}