Bump regex from 2025.11.3 to 2026.1.15

Bumps [regex](https://github.com/mrabarnett/mrab-regex) from 2025.11.3 to 2026.1.15.
- [Changelog](https://github.com/mrabarnett/mrab-regex/blob/hg/changelog.txt)
- [Commits](mrabarnett/mrab-regex@2025.11.3...2026.1.15)

---
updated-dependencies:
- dependency-name: regex
  dependency-version: 2026.1.15
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Author: dependabot[bot]