Move to use RUBY_METHOD_FUNC in order to generate appropriate rdoc.
Move to use RUBY_METHOD_FUNC in order to generate appropriate rdoc.

Signed-off-by: Krzysztof Wilczynski <9bf091559fc98493329f7d619638c79e91ccf029@linux.com>

kwilczynski/ruby-fizzbuzz,kwilczynski/ruby-fizzbuzz,kwilczynski/ruby-fizzbuzz