Merge pull request rails#47702 from shouichi/class-cache-nodoc

Add nodoc to ActiveRecord::FixtureSet::ClassCache [skip ci]

Author: vipulnsward

activerecord/lib/active_record/fixtures.rb

@@ -467,7 +467,7 @@ class FixtureSet
 
     cattr_accessor :all_loaded_fixtures, default: {}
 
-    class ClassCache
+    class ClassCache # :nodoc:
       def initialize(class_names, config)
         @class_names = class_names.stringify_keys
         @config      = config