(docs deps): Bump remark-retext from 5.0.1 to 6.0.0

Bumps [remark-retext](https://github.com/remarkjs/remark-retext) from 5.0.1 to 6.0.0.
- [Release notes](https://github.com/remarkjs/remark-retext/releases)
- [Commits](remarkjs/remark-retext@5.0.1...6.0.0)

---
updated-dependencies:
- dependency-name: remark-retext
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]