Amended documentation example to create partials using gulp-wrap

[kahwee]

Amended based on #12

@lazd, doing this [gulp-wrap] with the backticks renders gulp-wrap without the link. I didn't add that in.

[lazd]

With #17, this becomes much easier. @kahwee or @wbyoung, would you be willing to send a (another) pull request outlining how to accomplish this using gulp-define-module? The relevant issue is #10.

[wbyoung]

It looks to me like you'd do this about the same way. I'll leave this to @kahwee to update. The resulting partial could be sent to gulp-define-module if desired, but wouldn't need to be.