Add regression test for macro matcher dollar suggestion

[Kuhai9801]

Fixes #157157.

Adds regression coverage for the nested matcher form with an extraneous $ before a macro fragment specifier.

The expected diagnostic points at the extra $ and suggests removing it, producing $e:expr.

Verification:

• git diff --check
• rustc +nightly-2026-05-28 --emit=metadata tests\ui\macros\macro-missing-fragment.rs

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