I've been meaning to do this for a while. Since the data files don't yet
have any consumers (apart from the script that turns them into the
Registry web page) now seemed like a good time.

https://github.com/schemeorg/registry.scheme.org/commit/ee0f8db22aa7a745085540f7283a4302c6d2dc15

Upgrade the syntax used in data files

- Drop the flat line-oriented format, which never made any sense for
   this application. Instead, group each record as its own top-level
   S-expression and encode the record fields as nested lists.

- Use strings instead of symbols for IDs (in preparation for POSE).

I checked using `diff` that generate.scm outputs an index.html
identical to the old one.