Add unit test for xmode bug discovered by anonymous pastebin user
user
```factor
IN: xmode.code2html.tests
USING: xmode.code2html xmode.catalog
tools.test multiline splitting memoize
kernel ;

[ ] [ \ (load-mode) reset-memoized ] unit-test

[ ] [
    <" <style type="text/css" media="screen" >
    *        {margin:0; padding:0; border:0;} ">
    string-lines "html" htmlize-lines drop
] unit-test```
assistant