strip away hyphen between param name + description

From [the JsDoc docs](http://usejsdoc.org/tags-param.html):

> You can add a hyphen before the description to make it more readable. Be sure to include a space before and after the hyphen.

Here's their example:

```javascript
/**
 * @param {string} somebody - Somebody's name.
 */
function sayHello(somebody) {
    alert('Hello ' + somebody);
}
```

This change handles this case so that instead of `"- Somebody's name"` the description of the `somebody` param above is just `"Somebody's name"`, which I think is preferable based on my interpretation of the docs.