* gc.c: [DOC] Fix call-seq for GC.start by @jasonrclark [Fixes GH-572]
  https://github.com/ruby/ruby/pull/572 [ci skip]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45377 b2dd03c8-39d4-4d8f-98ff-823fe69b080e