Bump nokogiri from 1.11.1 to 1.11.4 in /docs (paritytech#397)

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.11.1 to 1.11.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.11.1...v1.11.4)

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

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

docs/Gemfile.lock

@@ -54,8 +54,8 @@ GEM
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
-    mini_portile2 (2.5.0)
-    nokogiri (1.11.1)
+    mini_portile2 (2.5.1)
+    nokogiri (1.11.4)
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
     pathutil (0.16.2)