Bump nokogiri from 1.18.8 to 1.18.9 in /docs (#1579)

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.18.8 to 1.18.9.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.18.8...v1.18.9)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-version: 1.18.9
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/Gemfile.lock

@@ -223,7 +223,7 @@ GEM
     minitest (5.25.4)
     net-http (0.6.0)
       uri
-    nokogiri (1.18.8-x86_64-linux-gnu)
+    nokogiri (1.18.9-x86_64-linux-gnu)
       racc (~> 1.4)
     octokit (4.25.1)
       faraday (>= 1, < 3)