Support markdown in @author and @endpoint

[tfrancart]

Would be nice to link to a blog post or a website from the author name. Would be nice to display the list of endpoints not as technical URIs, but as readable names (but in that case I guess you need to be able to handle the case where the @endpoint value is a plain endpoint URL)

[ldodds]

I'll consider how best to do this. Using markdown for author names is probably simplest as we're using it elsewhere. Ditto for endpoints, but I also want to reliably get the base URL in order to build links.