add brackets

src/devtools/WebAudioGraphIntegrator.test.js

@@ -13,7 +13,7 @@ import {integrateWebAudioGraph} from './WebAudioGraphIntegrator';
 import * as oscillatorGainFixture from '../../fixtures/oscillatorGainParam';
 
 // Node.js environment doesn't provide some browser-specific APIs
-// (e.g. performance.now(), localStorage.getItem and localStorage.setItem)
+// (e.g. performance.now(), localStorage.getItem() and localStorage.setItem())
 // Mocking these ensures no errors are thrown when running tests.
 global.performance = {
   now: jest.fn(() => Date.now()),