Bump rdoc from 6.5.0 to 6.6.0

Bumps [rdoc](https://github.com/ruby/rdoc) from 6.5.0 to 6.6.0.
- [Release notes](https://github.com/ruby/rdoc/releases)
- [Changelog](https://github.com/ruby/rdoc/blob/master/History.rdoc)
- [Commits](ruby/rdoc@v6.5.0...v6.6.0)

---
updated-dependencies:
- dependency-name: rdoc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -193,7 +193,7 @@ GEM
     rbi (0.1.1)
       sorbet-runtime (>= 0.5.9204)
       yarp (>= 0.11.0)
-    rdoc (6.5.0)
+    rdoc (6.6.0)
       psych (>= 4.0.0)
     regexp_parser (2.8.2)
     reline (0.3.9)