src/vs/workbench/contrib/notebook/browser/viewModel/baseCellViewModel.ts/BaseCellViewModel/_removeCellDecoration
class BaseCellViewModel:	private _removeCellDecoration(decorationId: string) {
		const options = this._resolvedCellDecorations.get(decorationId);

		if (options) {
			this._cellDecorationsChanged.fire({ added: [], removed: [options] });
			this._resolvedCellDecorations.delete(decorationId);
		}
	}