Fix yaml parser issue

[mabras]

I was working on refinerycms, some values get parsed with new line (\n) in it:

h = {"confirm_changes" => "Any changes you've made will be lost. Are you sure you want to continue without saving?"}

#"---\nconfirm_changes: Any changes you've made will be lost. Are you sure you want to continue\n  without saving?\n"

https://eval.in/453954

So I had to use line_width => -1 to solve the problem.

[1st8]

Nice find, just cherry-picked it into my branch 👍