Pass through syntax tag for PRE blocks.

It's just Prolog and Python.
Add Mastodon link.
Misc. blah blah
This is concise code.
Cleanup and merge highlight into gemtext.
Add arrows to links; don't add extra PRE tag.
Update the README to reflect reality.

This is a Gemini-to-HTML5 converter, not a site generator.  (For that
you need make.)
Remove cruft.
Remove unused code.

Now that I'm just using this as a Gemini-to-HTML converter and driving
it with make there's no reason to keep the original script around.
Minor cleanup.

Implement prolog syntax highlighting with pipe/3.

I realized that if I just had a Gemini-to-HTML converter I can do
everything else "outside" the tool using existing tools (e.g. make and
friends.)  As cool as Prolog is, I'm not trying to reinvent every wheel.
(Like how, since I already depend on Python 3 for Pygments I also use it
for HTML escaping.)
minor cleanup
 remove that old file
minor cleanup
Comment out gemtext stand-alone clauses.

That's why the program appeared to hang, it was waiting to read from
stdin.  D'oh!
"Inline" the python doggerl for HTML escaping.
A handmade index file for now.
Removed my old cruft.

Gemini going forward.
HTML escapes

Should pre text be escaped too?  I think so...