Bump textlint from 12.1.1 to 15.5.1 in /dependencies

Bumps [textlint](https://github.com/textlint/textlint) from 12.1.1 to 15.5.1.
- [Release notes](https://github.com/textlint/textlint/releases)
- [Commits](textlint/textlint@v12.1.1...v15.5.1)

---
updated-dependencies:
- dependency-name: textlint
  dependency-version: 15.5.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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Author: dependabot[bot]