Name-Based UUID

Yields the RFC 9562 version 5 UUID of a name under a namespace: SHA-1 over the namespace UUID's 16 bytes followed by the UTF-8 bytes of the name, with the version and variant bits set (RFC 9562, section 5.5). The same namespace and name always give the same UUID, in every evaluator, so an identifier derived from a declaration, such as the UUID of its versionless URI, is stated in the declaration rather than computed in each consumer's code. The result is lower-case text, in the form `uuidFormat` names. A namespace that isn't a UUID in canonical text, or a name that isn't a string, is an evaluation error naming what was found, never a value.