Fix broken code example at entries/length.xml

The comment at the last line causes the example script to be loaded automatically in a broken state on window.onload.

The generated code ends up looking like this:

```javascript
window.onload = function() {$(document.body).click(function () {
  $(document.body).append($("<div>"));
  var n = $("div").length;
  $("span").text("There are " + n + " divs." +
                 "Click to add more.");
}).trigger('click'); // trigger the click to start};
```

Thus the ending curly brace } gets commented out and it results in a script error.