Add rule for Web Storage API (localStorage, sessionStorage)

[EvgenyOrekhov]

1. Accessing localStorage or sessionStorage objects can throw SecurityError DOMException
2. "Set" operations can throw QuotaExceededError DOMException
3. localStorage and sessionStorage can be null (not sure if this is per spec, but Safari, Mobile Safari, and Chrome Mobile WebView definitely do this)

Reference: https://html.spec.whatwg.org/multipage/webstorage.html