Media Query documentation should not use `@` symbols in links

Hi there,

The rendered documentation page for Media.elm has a couple of links to MDN's @media documentation pages, and due to the @ symbol appearing in these URLs, the Markdown parser seems to be turning them into mailto links instead of normal web links.

One specific case can be found here: http://package.elm-lang.org/packages/rtfeldman/elm-css/13.1.1/Css-Media#MediaType

The link it references https://developer.mozilla.org/en-US/docs/Web/CSS/@media#Media_types becomes mailto:https://developer.mozilla.org/en-US/docs/Web/CSS/@media#Media_types

Not sure if this should be a bug filed with elm-markdown or not, but I thought I'd start here.