Clarify whether `Procedure.search`'s `date` parameter filters based on `performed` `lastUpdated`

This row in the Procedure > Parameters [table](https://fhir.cerner.com/millennium/r4/clinical/summary/procedure/#parameters) is unclear about how `date` is used:

<img width="817" alt="image" src="https://github.com/cerner/fhir.cerner.com/assets/1088051/d5a89af4-04fb-4d83-b063-b5cfed2b0613">