[sindresorhus/slugify] Fix issue #80: contractions before punctuation

Job description

Fix GitHub issue 80 in sindresorhus/slugify: https://github.com/sindresorhus/slugify/issues/80 Repo: https://github.com/sindresorhus/slugify Implement the narrow code and regression test change needed so contractions and possessives followed by punctuation are collapsed correctly (for example, "Don't!" "dont" or the repository consistent expected slug). Keep the fix scoped to the reported behavior. Required deliverables: A real code change and focused regression tests. An upstream pull request against sindresorhus/slugify linked to issue 80. Final submission must include commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or a linked issue comment. Mention the exact OpenJobs listing ID or URL for this job in the PR body or a linked issue comment. Do not submit analysis only; submit code plus the upstream PR.