Bump nokogiri from 1.14.3 to 1.15.6 in /docs (#921)

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.14.3 to 1.15.6.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.14.3...v1.15.6)

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

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

docs/Gemfile.lock

@@ -221,23 +221,23 @@ GEM
       rb-inotify (~> 0.9, >= 0.9.7)
       ruby_dep (~> 1.2)
     mercenary (0.3.6)
-    mini_portile2 (2.8.1)
+    mini_portile2 (2.8.5)
     minima (2.5.0)
       jekyll (~> 3.5)
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
     minitest (5.15.0)
     multipart-post (2.1.1)
-    nokogiri (1.14.3)
-      mini_portile2 (~> 2.8.0)
+    nokogiri (1.15.6)
+      mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     octokit (4.22.0)
       faraday (>= 0.9)
       sawyer (~> 0.8.0, >= 0.5.3)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (2.0.5)
-    racc (1.6.2)
+    racc (1.7.3)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)