tiny legibility issue in docs (perhaps md limitation)

[mfeif]

Re: https://github.com/lektor/lektor-website/blob/master/content/docs/content/contents.lr#L89

On my standard Chrome setup on a Mac, it renders like this:

Sure would be nice if those four dashes could be wrapped in <nobr>... can either embed the tags right in the md, or style the code tags:

code { white-space: nowrap; }

This may have unintended consequences elsewhere in the docs though, so before I do a PR, I thought I'd just bring it up. :-)