src/vs/workbench/contrib/notebook/browser/contrib/outline/notebookOutline.ts/NotebookQuickPickProvider/getQuickPickElements
class NotebookQuickPickProvider:	getQuickPickElements(): IQuickPickOutlineElement<OutlineEntry>[] {
		const bucket: OutlineEntry[] = [];
		for (let entry of this._getEntries()) {
			entry.asFlatList(bucket);
		}
		const result: IQuickPickOutlineElement<OutlineEntry>[] = [];
		const { hasFileIcons } = this._themeService.getFileIconTheme();
		for (let element of bucket) {
			// todo@jrieken it is fishy that codicons cannot be used with iconClasses
			// but file icons can...
			result.push({
				element,
				label: hasFileIcons ? element.label : `$(${element.icon.id}) ${element.label}`,
				ariaLabel: element.label,
				iconClasses: hasFileIcons ? getIconClassesForModeId(element.cell.language ?? '') : undefined,
			});
		}
		return result;
	}