- Rather than include all the separate rationale information,
    we'll provide links to the website.  This adds links to the
    already-included SRFI-105 and SRFI-110, since they already include
    some rationale.

- Add a few stub .md files.  That way, if you click on a link in a local
    generated HTML file, it'll show a stub file that points you to the
    real content.  Much better than simply failing.