US Core heart-rate example is not conformant to http://hl7.org/fhir/StructureDefinition/heartrate

https://www.hl7.org/fhir/us/core/Observation-heart-rate.xml.html includes a heart rate like:

  <valueQuantity>
    <value value="44.0"/>
    <unit value="{beats}/min"/>
    <system value="http://unitsofmeasure.org"/>
    <code value="{beats}/min"/>
  </valueQuantity>

This conflicts with https://www.hl7.org/fhir/heartrate.html which indicates that the code value must have the fixed value /min.

I've read https://chat.fhir.org/#narrow/stream/179166-implementers/topic/UCUM.20bpm.20-.20heart.20rate.20at.20wrist and I understand that these are really the same concept in UCUM, but our systems do not.

I also read https://jira.hl7.org/browse/FHIR-13573 and I believe that FHIR-I made the wrong decision on that one... we would prefer a fixed string of "{beats}/min" vs "/min", even if the "{beats}" is just for humans.

However, assuming that ship has sailed, I think US Core should live with that decision and update this sample to have a code value of "/min".