* bignum.c: Reorder functions to decrease forward reference.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41822 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Useless comment removed.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41823 b2dd03c8-39d4-4d8f-98ff-823fe69b080e