test(semantic): pin the rejection of an expansion zipping sibling repetitions

[orizi]

An expansion block whose placeholders come from two sibling pattern
repetitions is rejected at declaration time (E2199). rustc accepts the
declaration and zips equal-length repetitions at expansion; staying
stricter is a deliberate decision (2026-08-04) - the shape is confusing
and the declaration-time error is actionable.

Co-Authored-By: Claude Fable 5 noreply@anthropic.com

[reviewable-StarkWare]

This change is 

[orizi]

• test(semantic): pin the rejection of an expansion zipping sibling repetitions #10316 👈 (View in Graphite)
• main

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[cursor]

PR Summary

Low Risk
Test-only change; no compiler logic modified.

Overview
Adds a snapshot test in inline_macros that locks in Cairo’s behavior when a macro expansion block mixes placeholders from two sibling pattern repetitions (e.g. $($a:ident),* ; $($b:ident),* with body $($a + $b + )*).

The test expects E2199 at macro declaration time (Macro placeholder 'b' is from a different repetition than the one driving this expansion block), documenting that this shape is intentionally rejected even though rustc would accept the rule and zip equal-length repetitions at expansion.

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[TomerStarkware]

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Reviewable status: complete! all files reviewed, all discussions resolved (waiting on eytan-starkware).