extensions/typescript-language-features/src/languageFeatures/references.ts/register
export function register(
	selector: DocumentSelector,
	client: ITypeScriptServiceClient
) {
	return conditionalRegistration([
		requireSomeCapability(client, ClientCapability.EnhancedSyntax, ClientCapability.Semantic),
	], () => {
		return vscode.languages.registerReferenceProvider(selector.syntax,
			new TypeScriptReferenceSupport(client));
	});
}