src/vs/workbench/contrib/localization/browser/localeService.ts/WebLocaleService/setLocale
class WebLocaleService:	async setLocale(languagePackItem: ILanguagePackItem): Promise<boolean> {
		const locale = languagePackItem.id;
		if (locale === language || (!locale && language === navigator.language)) {
			return false;
		}
		if (locale) {
			window.localStorage.setItem('vscode.nls.locale', locale);
		} else {
			window.localStorage.removeItem('vscode.nls.locale');
		}
		return true;
	}