[e] (0) escape more characters in example data: url (text track section)
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=27161
Affected topics: Video Text Tracks

git-svn-id: https://svn.whatwg.org/webapps@8862 340c8d12-0b0e-0410-8428-c7bf67bfef74