Bump nokogiri from 1.19.3 to 1.19.4 in /docs (#3357)

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.19.3 to 1.19.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](https://github.com/sparklemotion/nokogiri/compare/v1.19.3...v1.19.4)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-version: 1.19.4
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Nat Dean-Lewis <94526761+natdeanlewissoftwire@users.noreply.github.com>

docs/Gemfile.lock

@@ -229,11 +229,11 @@ GEM
     minitest (5.27.0)
     net-http (0.9.1)
       uri (>= 0.11.1)
-    nokogiri (1.19.3-arm64-darwin)
+    nokogiri (1.19.4-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.19.3-x86_64-darwin)
+    nokogiri (1.19.4-x86_64-darwin)
       racc (~> 1.4)
-    nokogiri (1.19.3-x86_64-linux-gnu)
+    nokogiri (1.19.4-x86_64-linux-gnu)
       racc (~> 1.4)
     octokit (4.25.1)
       faraday (>= 1, < 3)