Introduce a `book.toml` in the `nostarch` directory, which matches the
existing `book.toml` except for specifying the correct relative input
and output directories and disabling the `trpl-note` preprocessor. This
also lets us simplify the invocation in the `nostarch.sh` script a bit,
by providing the configuration directly in the file.
Use the newly-introduced `mdbook-trpl-note` to render accessible and
semantic HTML for the notes/callouts in the book. This currently applies
to the nostarch version as well, so a follow-on change will update the
build process to undo that. Add CSS so the new note rendering matches
the existing rendering of blockquotes. (We might want to change that at
some point, but for now the goal is to maximizing continuity.)
Chris Krycho
David
Jonas Berlin
Steve Klabnik