src/vs/editor/standalone/browser/standaloneLanguages.ts/registerSignatureHelpProvider
export function registerSignatureHelpProvider(languageSelector: LanguageSelector, provider: languages.SignatureHelpProvider): IDisposable {
	const languageFeaturesService = StandaloneServices.get(ILanguageFeaturesService);
	return languageFeaturesService.signatureHelpProvider.register(languageSelector, provider);
}