extensions/markdown-language-features/src/logging.ts/VsCodeOutputLogger/data2String
class VsCodeOutputLogger:	private static data2String(data: any): string {
		if (data instanceof Error) {
			if (typeof data.stack === 'string') {
				return data.stack;
			}
			return data.message;
		}
		if (typeof data === 'string') {
			return data;
		}
		return JSON.stringify(data, undefined, 2);
	}