docs: clarify unsupported operators in operator precedence

[atorrers]

Summary

Clarify operator-precedence.adoc by documenting that chained equality (a == b == c) is unsupported and by replacing a vague assignment-table note with an explicit unsupported operator list for shift/bitwise compound assignments (<<=, >>=, &=, ^=, |=).

---

Type of change

Please check one:

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

⚠️ Note:
To keep maintainer workload sustainable, we generally do not accept PRs that
are only minor wording, grammar, formatting, or style changes.
Such PRs may be closed without detailed review.

---

Why is this change needed?

operator-precedence.adoc already documented unsupported chained comparisons (a < b < c) but did not document unsupported chained equality (a == b == c), while related operator pages already do. The assignment row also used a generic "Second line not yet supported" note instead of explicitly naming unsupported operators. This mismatch can mislead users into unsupported syntax that fails at parse/compile time.

---

What was the behavior or documentation before?

• No explicit chained-equality limitation in operator-precedence.adoc.
• Assignment table second line used a vague unsupported note without naming the actual unsupported operators.

---

What is the behavior or documentation after?

• Added a Chained equality section with a concrete rewrite pattern: a == b && b == c.
• Assignment table now explicitly states that shift/bitwise compound assignment operators (<<=, >>=, &=, ^=, |=) are not supported.

---

Related issue or discussion (if any)

---

Additional context

This is a docs-only, low-risk change that aligns this page with existing operator-reference coverage and with current parser-supported assignment operators, reducing avoidable user confusion.

---

Note

Low Risk
Docs-only changes that clarify unsupported Cairo syntax; no runtime or API behavior is modified.

Overview
Updates operator-precedence.adoc to explicitly document unsupported syntax. It replaces the vague assignment-table note with an explicit list of unsupported shift/bitwise compound assignments (<<=, >>=, &=, ^=, |=), and adds a new Chained equality section stating a == b == c is not supported and should be written as a == b && b == c.

^{Written by Cursor Bugbot for commit fed4465. This will update automatically on new commits. Configure here.}

[reviewable-StarkWare]

This change is 

[orizi]

@orizi made 1 comment.
Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on atorrers).

---

docs/reference/src/components/cairo/modules/language_constructs/pages/operator-precedence.adoc line 29 at r1 (raw file):

| Assignment                            | `=` `+=` `-=` `*=` `/=` `%=`

                                          `<<=` `>>=` `&=` `^=` `\|=`    | Shift and bitwise compound assignment operators are not supported.

split into rows instead.