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