Fix typo for gt char

Sorry. Found typo in last patch. Actually you are right and its kinda dirty. I've looked over [marked](https://github.com/chjj/marked/blob/master/lib/marked.js#L1076) module source and there is replace function for escape symbols:

```JavaScript
function escape(html, encode) {
  return html
    .replace(!encode ? /&(?!#?\w+;)/g : /&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&#39;');
}
```

So its kinda of reverse operation. And I agree it's pretty dirty fix.