Required texts on CodeableConcepts

[qligier]

Should the CodeableConcept texts be mandatory or not?
In the base specification, the text and code.display are optional, so a document could contain only the code. For required value sets, this may not be an issue because we also provide the value sets with translated displays. For other cases (no value set, or example/extendable), this may be a bigger issue.

For ahdis, this is over-constrained and not the way to go.