`bundle exec rake rdoc` generates `Racc` document for RDoc

[okuramasafumi]

A document generated by bundle exec rake rdoc in RDoc repository includes Racc inside "Class and Module index". It's weird that references to Racc class seem not to exist.
I've looked through source code but didn't find any clue.

[olleolleolle]

What if... #1156 was used, and you tried again, would it happen, then, too?

[st0012]

It's generated because Racc will be included in generated files like lib/rdoc/rd/block_parser.rb.