src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts/NotebookContribution/_getCellUndoRedoComparisonKey
class NotebookContribution:	private static _getCellUndoRedoComparisonKey(uri: URI) {
		const data = CellUri.parse(uri);
		if (!data) {
			return uri.toString();
		}

		return data.notebook.toString();
	}