src/vs/workbench/contrib/notebook/browser/notebookEditorWidget.ts/NotebookEditorWidget/cellIsHidden
class NotebookEditorWidget:	private cellIsHidden(cell: ICellViewModel): boolean {
		const modelIndex = this.viewModel!.getCellIndex(cell);
		const foldedRanges = this.viewModel!.getHiddenRanges();
		return foldedRanges.some(range => modelIndex >= range.start && modelIndex <= range.end);
	}