Adds missing demo stuff from cf-forms.

I do think we should be exposing these comments somehow on the rendered page. Especially for something like this where you're demoing the _lack_ of a change from the default browser styling. But I'm not sure where to file an issue about it, since this probably occurs in many components' repos.

If we want to keep the default view lean, perhaps we could add something to the demo Jade template that enables a hidden note that you can reveal by clicking an icon or something. What do you think?