Using "immediate" parents to describe the parent() method, per #537

This is definitely an improvement, but I think we can do even better. Maybe something like this…

> Given a jQuery object that represents a set of DOM elements, the `parent()` method traverses to the immediate parent of each of these elements in the DOM tree and constructs a new jQuery object from the matching elements.

What do you think, @mattlunn? If you like it, feel free to update this PR and I'll merge it in.