YAML file enumeration value superstructures

[dthaler]

In the YAML file format, superstructures is not allowed for enumeration values.

This limitation resulted in bugs like #100 since it could not be validated. If instead, https://gedcom.io/terms/v7/enum-BIC had had something like

superstructures:
  "https://gedcom.io/terms/v7/SLGC": "{0:1}"

then the bug with

1 BAPL
2 STAT BIC

would have been automatically detected.

[dthaler]

Another possibility would be to allow value of to contain a URI of a structure, not just a URI of an enum set. E.g.:

https://gedcom.io/terms/v7/enum-BIC might have:

value of:
  - "https://gedcom.io/terms/v7/SLGC"

instead of what it has now:

value of:
  - "https://gedcom.io/terms/v7/enumset-ord-STAT"

The former is more specific than the latter, since multiple structures have type https://gedcom.io/terms/v7/enumset-ord-STAT but BIC is only legal under SLGC.

[dthaler]

GEDCOM Steering Commitee Discussion 11/30/2023:
We can use 3 different enumsets (for SLGC, SLGS, and for others), can generate a PR to review for next time.

[dthaler]

Subsequent discussion on FamilySearch/GEDCOM#399 resulted in filing issue FamilySearch/GEDCOM#400 and marking this as "next major".