* ext/date/date_core.c: [DOC] Clean up whitespace, examples, and typos
  in date_core based on a patch by @vipulnsward [Fixes GH-724]
  https://github.com/ruby/ruby/pull/724


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47895 b2dd03c8-39d4-4d8f-98ff-823fe69b080e