Ruby

• ext/psych/lib/psych/visitors/yaml_tree.rb: quote strings that begin
  with non-word characters. Thanks Alex Tambellini!
• test/psych/test_yaml.rb: appropriate test case

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38367 b2dd03c8-39d4-4d8f-98ff-823fe69b080e