extensions/ipynb/src/deserializers.ts/createNotebookCellDataFromMarkdownCell
function createNotebookCellDataFromMarkdownCell(cell: nbformat.IMarkdownCell): NotebookCellData {
	const cellData = new NotebookCellData(
		NotebookCellKind.Markup,
		concatMultilineString(cell.source),
		'markdown'
	);
	cellData.outputs = [];
	cellData.metadata = { custom: getNotebookCellMetadata(cell) };
	return cellData;
}