Use set-process-coding-system for UTF-8.

Instead of set-terminal-coding-system, which is global.
Various changes to Scribble parsing.

- Handle `deftogether` HTML, too -- and in the process greatly simplify
  intrapara-anchor.

- Display the kind and provide information in light grey on one line.

- Return #f for the other not-found case.

- Add unit tests.