Update hl7.fhir.uv.cql.md

[brynrhodes]

Resolution for https://jira.hl7.org/browse/FHIR-49625

[grahamegrieve]

I think that something like this is closer to a real plain language summary:

General

Clinical Quality Language (CQL) is a computer programming language used for decision support, public health reporting, and research/trial eligibility criteria.

This standard defines the CQL language itself, and ways to use it with FHIR (as the most general purpose way to access healthcare information systems consistently). Healthcare providers can use this standard to share the rules that support clinical decision-making and quality reporting
with each other, and software developers get clear guidelines for building systems that support this.

Sharing this knowledge lead to economies of scale and better healthcare outcomes for less cost.

[brynrhodes]

Okay, I incorporated most of these changes, but I fixed the bit about this being the definition of CQL itself, this is just the Using CQL With FHIR IG, CQL itself is defined in http://cql.hl7.org