abandon wrapping if the line contains no space. [ruby-dev:36045]
fix: #342
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@19511 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
<evanfarrar at gmail.com> in [ruby-doc:1382] applied.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@16811 b2dd03c8-39d4-4d8f-98ff-823fe69b080e