Create an "Array-Like" type

[dmethvin]

As suggested by @timmywil in #686 (comment), add an "Array-Like" type to our Types page to clarify when a method accepts more than just Array. Perhaps something like this:

Array-Like - Either a true JavaScript Array or a JavaScript Object that contains a numeric length property. This latter case includes array-like objects commonly encountered in web-based code such as the Arguments object and the NodeList object returned by many DOM methods. Note that when a jQuery API accepts either plain Objects or Array-Like objects, a plain Object with a numeric length property will trigger the Array-Like behavior.

[arthurvr]

Yup, 👍. I'll take this one.