Fixing a stupid word typo for 2 of the obsersers options

I stupidly made a word typo for 2 of the observers options.

```javascript
var observers = {
  attributes: options && options.observers && options.observers.attributes || false,
  childList: options && options.observers && options.observers.childList ? options.types.childList : true,
  characterData: options && options.observers && options.observers.characterData || false,
  subtree: options && options.observers && options.observers.subtree ? options.types.subtree : true,
  attributeFilter: options && options.observers && options.observers.attributeFilter || []
};
```

2 `types` were left in the middle, residue of my first local implementation, before I renamed everything to open the first PR.

It was transparent and not used because of default values.