Remove comments which are inconsistent with actual dictionary & remove unused entry

[Chris0296]

Description

Removed comment table which is inconsistent with the actual mappings in the dictionary and as such is unhelpful to users. Removed unused 'SNOMED CT US Edition' entry from the dictionary.

Github Issue: https://github.com/cqframework/cqf-tooling/issues/93 https://github.com/cqframework/cqf-tooling/issues/94

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• [x] Code compiles without errors
• [ ] Tests are created / updated
• [ ] Documentation is created / updated

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