doc: fix grammar errors in operator-expressions.adoc

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• doc: fix grammar errors in operator-expressions.adoc #9765 👈 (View in Graphite)
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PR Summary

Low Risk
Documentation-only wording/grammar fixes with no runtime or API behavior changes, so regression risk is minimal.

Overview
Improves wording in operator-expressions.adoc by fixing grammar, pluralization, and verb agreement (e.g., operators/operands, translates/propagates, and plural operators/types/levels) to make the operator expression documentation read correctly and consistently.

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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 eytan-starkware).

[orizi]

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