The former toSCFG implementation had several shortcomings which
did not consider a few possibilities SCFG provides. Details were lined
out in #7465.
The new interface needs more verbosity, but reflects better the
properties of the SCFG format. I also chose to use the names used in the
[Specification].
[Specification]: https://git.sr.ht/~emersion/scfg#specification-draft