Wrong documentation for padding

The doc says

> The value is relative to the visible height of the area, the default is 0.5 and the minimal value is 0.3

But according to the code both default and minimal values are 0.1

```
function bufferPadding() {
  return viewport.outerHeight() * Math.max(0.1, +attrs.padding || 0.1);
}
```

I can fix the code to make it according to the doc.
Otherwise the doc should be fixed.
