add missing `:nodoc:` for recent refactorings. [ci skip]

Adding `# :nodoc:` to the parent `class` / `module` is not going
to ignore nested classes or modules.

There is a modifier `# :nodoc: all` but sadly the containing class
or module will continue to be in the docs.

/cc @sgrif

1 files changed, 1 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/attribute_set.rb b/activerecord/lib/active_record/attribute_set.rb
index 5e5f7ca1b5..ed2500a675 100644
--- a/activerecord/lib/active_record/attribute_set.rb
+++ b/activerecord/lib/active_record/attribute_set.rb
@@ -30,7 +30,7 @@ module ActiveRecord
       super
     end
 
-    class Builder
+    class Builder # :nodoc:
       def initialize(types)
         @types = types
       end
@@ -48,6 +48,5 @@ module ActiveRecord
     protected
 
     attr_reader :attributes
-
   end
 end