fix: update acorn, fix tests

[mdjermanovic]

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What is the purpose of this pull request?

Recently release acorn v8.16.0 changes some parsing error messages, and that breaks our tests (https://github.com/eslint/js/actions/runs/22198873458/job/64206263995).

What changes did you make? (Give an overview)

Updated acorn dependency to the latest version and updated failing tests.

Related Issues

Is there anything you'd like reviewers to focus on?

[lumirlumir]

LGTM, thanks!

Would it be okay to use fix as the PR prefix? Based on the discussion in eslint/workflows#33 (comment), it seems dependencies updates are treated as fix.

[mdjermanovic]

Makes sense, I wasn't aware of that. Also, per the description on https://github.com/acornjs/acorn/releases/tag/8.16.0, some bug fixes related to parsing are now released in acorn v8.16.0, so those fixes apply to espree's parsing as well.