Fix variable expansion in yield

The AnyMethod#param_seq removes string after "#" as comment,
but comment token is removed in
Parser::Ruby#parse_method_or_yield_parameters.
This commit fixes it.

Author: aycabta

lib/rdoc/any_method.rb

@@ -276,8 +276,7 @@ def param_seq
       # &block
       params.sub!(/,?\s*&\w+/, '')
 
-      block = @block_params.gsub(/\s*\#.*/, '')
-      block = block.tr("\n", " ").squeeze(" ")
+      block = @block_params.tr("\n", " ").squeeze(" ")
       if block[0] == ?(
         block.sub!(/^\(/, '').sub!(/\)/, '')
       end