Add use statement for definition - hopefully people will know that go…

Created by: eileenmcnaughton

…es at the top of the file

Created by: totten

FWIW... if you check out the Symfony dev docs, they use this same style a lot: put use at the top of the snippet along with some whitespace (examples, examples).

A comment might improve it, but I think this change is 'better in than out'.

Created by: eileenmcnaughton

@totten feel free to merge on that basis as I don't see it getting more love