docs: clarify mixed comparison/equality in operator precedence

[Elena343-ai]

Summary

Document that mixed consecutive comparison/equality operators such as a < b == c and a == b < c are also unsupported in the operator precedence reference, and point readers to explicit conjunctions or parenthesized boolean comparisons instead.

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Type of change

• Bug fix (fixes incorrect behavior)
• New feature
• Performance improvement
• Documentation change with concrete technical impact
• Style, wording, formatting, or typo-only change

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Why is this change needed?

The operator precedence page currently groups comparison and equality operators in the same precedence row and explains left-to-right associativity, but it only documents unsupported homogeneous chains such as a < b < c and a == b == c. That leaves a real ambiguity for mixed forms like a < b == c and a == b < c, which users can reasonably expect to parse from the precedence table alone. The parser rejects these forms with E1028.

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What was the behavior or documentation before?

The page did not state that mixed consecutive comparison/equality operators are rejected.

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What is the behavior or documentation after?

The page explicitly documents that mixed forms such as a < b == c and a == b < c are unsupported and points to explicit conjunctions or parenthesized boolean comparisons instead.

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Related issue or discussion (if any)

N/A

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Additional context

This matches the parser behavior for consecutive comparison/equality operators and follows the recent docs: clarify ... operator-documentation pattern already merged in this repository.

[reviewable-StarkWare]

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[orizi]

@orizi reviewed 1 file and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on Elena343-ai).