extensions/markdown-language-features/src/languageFeatures/smartSelect.ts/MdSmartSelect/provideSelectionRanges
class MdSmartSelect:	public async provideSelectionRanges(document: ITextDocument, positions: vscode.Position[], _token: vscode.CancellationToken): Promise<vscode.SelectionRange[] | undefined> {
		const promises = await Promise.all(positions.map((position) => {
			return this.provideSelectionRange(document, position, _token);
		}));
		return promises.filter(item => item !== undefined) as vscode.SelectionRange[];
	}