build(deps): bump racc from 1.5.2 to 1.6.0 in /docs

Bumps [racc](https://github.com/tenderlove/racc) from 1.5.2 to 1.6.0.
- [Release notes](https://github.com/tenderlove/racc/releases)
- [Changelog](https://github.com/ruby/racc/blob/master/ChangeLog)
- [Commits](https://github.com/tenderlove/racc/compare/v1.5.2...v1.6.0)

---
updated-dependencies:
- dependency-name: racc
  dependency-type: indirect
  update-type: version-update:semver-minor
...

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

docs/Gemfile.lock

@@ -246,7 +246,7 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.6)
-    racc (1.5.2)
+    racc (1.6.0)
     rainbow (3.0.0)
     rake (13.0.6)
     rb-fsevent (0.11.0)