build(deps): bump nth-check from 1.0.2 to 2.1.1 in /docs

Bumps [nth-check](https://github.com/fb55/nth-check) from 1.0.2 to 2.1.1.
- [Release notes](https://github.com/fb55/nth-check/releases)
- [Commits](fb55/nth-check@v1.0.2...v2.1.1)

---
updated-dependencies:
- dependency-name: nth-check
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]