- new dir for markup tools
  misc/util/d/tools/markup_conversion
- start looking at tools for converting
  - endnotes from binary to inline
  - sisu.rb to sisu spine in d
  - look at conversion of document headers to yaml
    from
    - bespoke sisu headers (original .rb)
    - sdlang
    - toml

- the good
  - works
  - project looks pretty clean
- the bad
  - subprojects built externally
  - not suitable for debian packaging

- subprojects with "manual" git download where
  upstream git lacks meson.build
- imageformats git tag (version) pinned, else
  build fails

- yaml only: config, make & headers
  (yaml is converted directly to struct)
- toml removed: preemptively remove confusion of
  having multiple config formats
  (toml was converted to json & json to struct)
- json removed (intermediate representation):
  takes out intermediate conversion to json which
  could be attractive to have if there are
  multiple formats