Re: [dom] Added an example showing feature detection with supports() (#144)

I think the example becomes

```js
// Will return true or false depending on whether the user agent implements the given token for <link rel>
document.createElement("link").relList.supports(token)

// Will always throw a TypeError since the class attribute has no supported tokens list
document.createElement("div").classList.supports(token)
```

---
Reply to this email directly or view it on GitHub:
https://github.com/whatwg/dom/pull/144#issuecomment-171392054