When a client calls $validate-code, the server returns the 'code being validated' in the code parameter, along with a flag for whether the code is valid or not. Exactly how this works is a bit unclear when the code comes from a code system that allows more than one representation for a code, but has a preferred representation - which is the code? (Code system examples: any case insensitive code system, and many code systems with a grammar that also define a normal form).

We should explicitly document that the code parameter is the code that the client passed in the request, and that if there's a 'normal' or 'preferred' representation for the concept that the code identified, the server should return that in a parameter name ```normalized-code```

See LOINC and case sensitivity for discussion