Drawer type doc error

First of all, thank you for provide so nicely lib and so flexible. And sorry for my english

On the Drawer doc, if you use `data-type="persistent"` on the button, works fine, but when you open and close with javascript `$('#navdrawerDefault').navdrawer('show')`, this create overlay upside the menu and all page. Using `data-type="persistent"` on the div content, works like a charm

Url: https://daemonite.github.io/material/docs/4.1/material/navigation-drawer/#persistent-drawer
Actual code:

```
Launch persistent drawer

```

Working code:

```
Launch persistent drawer

```

I don't make the change and commit for revision, because I don't know if this is a error of code or error of documentation

Using button on header for open

Using javascript method

With my suggestion