* lib/optparse.rb: [DOC] Add example of generating help with optparse.
  Patch by @joelmccracken documenting-ruby/ruby#19
  https://github.com/documenting-ruby/ruby/pull/19


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45195 b2dd03c8-39d4-4d8f-98ff-823fe69b080e