Fix comments with non-matching quote being treated as strings

[craigerm]

Hey there,

I'm not sure if this repo is still maintained, so feel free to ignore if not.

This related to the bug in Doiuse:
anandthakker/doiuse#192

The parser will treat a comment as a string if it doesn't have a matching quote.

Example:

# Correct
echo "/* comment with matching quote */" | node example.js

TOKEN [ 'comment', '/* comment with matching quote */' ]
TOKEN [ 'root', '\n' ]

# Incorrect
echo "/* comment with ' single quote */" | node example.js

TOKEN [ 'string', "/* comment with ' single quote */\n" ]
[css-tokenize] unfinished business [ [ 'root' ], [ 'comment' ]

Thanks for your time!
Craig