src/vs/workbench/contrib/notebook/browser/contrib/coreActions.ts/renderAllMarkdownCells
function renderAllMarkdownCells(context: INotebookActionContext): void {
	context.notebookEditor.viewModel.viewCells.forEach(cell => {
		if (cell.cellKind === CellKind.Markup) {
			cell.updateEditState(CellEditState.Preview, 'renderAllMarkdownCells');
		}
	});
}