Enumerator `@param` tags are never validated against the enumerator's fields

[pepone]

@param tags are permitted on enumerators (only_operations_have_parameters in slicec/src/validators/comments.rs allows Entities::Enumerator), but unlike operation parameters (validate_param_tags in slicec/src/validators/operations.rs) the tag's identifier is never checked against the enumerator's fields, and nothing rejects the tag on an enumerator that has no fields. All three of these compile without a single lint:

module tests

enum E {
    /// @param nmae: typo, no field is called 'nmae'
    A(name: string)

    /// @param x: this enumerator has no fields
    B
}

enum Status : int32 {
    /// @param code: enumerators of a basic enum can never have fields
    Ok = 0
}

With #818, a variant field only receives a comment when a @param tag names it, so the typo above silently produces an undocumented field in the generated code; the other two tags are silently discarded.

Suggested fix: validate enumerator @param identifiers against enumerator.fields() the same way validate_param_tags does for operations. That also rejects @param on fieldless and basic-enum enumerators.

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Found while reviewing #818 (Claude Fable 5.1, cross-checked with Codex; the silent acceptance was confirmed by compiling the snippet above and observing zero diagnostics). Not yet human-triaged.