Revert "Update specifications/conceptual-model-specification.md" because it was supposed to be applied to a branch.
Revert "Update specifications/conceptual-model-specification.md" because it was supposed to be applied to a branch.

This reverts commit ac9d70df0deb42ea0c2a32346dd31bc9a30dc7ce.

FamilySearch/gedcomx-java,brenthale/gedcomx-java,brenthale/gedcomx-java