Add guidance to the Procedure profile to express sdoh category

Proposal Will provide guidance on the  Screening and Assessments guidance page to indicate Implementers can choose to categorize procedures as an SDOH procedure or, indirectly by inspecting referenced ServiceRequest. Background The Procedure category element is optional and not considered "core".  Also, as the commenter points out, the max =1 cardinality on this element limits US Core's ability to constrain it since it may have multiple interpretations and meanings in different clinical domains. Constraining it to a specific definition may not accurately reflect the intended use.   The  US Core Procedure Profile may be used to "record a completed service or intervention"  and is part of the related activities illustrated on the Screenings and Assessments page. Implementers can choose to categorize procedures as an SDOH procedure or , as the commenter suggests, indirectly through the referenced ServiceRequest.