rails/rails — pull request #6699 by takkanm (2012-06-11 05:12:11+00:00)
Title: fix warning in Ruby2.0.0

I found following warning in Ruby2.0.0dev(2012-06-11 trunk 36028).

```
rails/activesupport/lib/active_support/multibyte/chars.rb:136: warning:
character class has duplicated range: /\b('?[\S])/
```