src/vs/workbench/api/common/extHostNotebookDocument.ts/ExtHostNotebookDocument/_changeCellMetadata
class ExtHostNotebookDocument:	private _changeCellMetadata(index: number, newMetadata: notebookCommon.NotebookCellMetadata): void {
		const cell = this._cells[index];
		cell.setMetadata(newMetadata);
	}