src/vs/workbench/api/common/extHostTypes.ts/NotebookCellOutputItem/json
class NotebookCellOutputItem:	static json(value: any, mime: string = 'application/json'): NotebookCellOutputItem {
		const rawStr = JSON.stringify(value, undefined, '\t');
		return NotebookCellOutputItem.text(rawStr, mime);
	}