gemserv: Non-gemini files have mime type text/gemini

[int 80h]

On Thu May 28, 2020 at 11:38 AM EDT, tastytea wrote:
> For example, <gemini://tastytea.de/dotfiles/.emacs.d/init.el> returns
> “20 text/gemini”¹. Files without a file extension are also returned
> as
> text/gemini.
>
> I think text/plain is better suited as the default type for unknown
> files.

That's probably a good idea. The only difference is formatting so that
that would make more sense. Thanks.

int 80h