MedicalAction action field in doc could be changed to a more detailed field

In MedicalAction, there is the "action" field which can be either of type Procedure, Treatment, RadiationTherapy or TherapeuticRegimen. Instead of it being named "action" (in a phenopacket json file that is generated with the phenopacket-tools, there is no such field/id), we could indicate that the id in the corresponding json is either "procedure", "treatment", "radiationTherapy" or "therapeuticRegimen".

Locate MedicalAction in the phenopacket schema and inspect how phenopacket-tools generates its JSON. Confirm how the action field is represented and determine whether the output should use procedure, treatment, radiationTherapy, or therapeuticRegimen as the corresponding identifier. Done means the schema and generated JSON consistently use the more specific field names.

Written by the indexing model from the issue text.