Fix character class for end-of-line attributes

This test will be fooled by a block like this:

```jade
script weirdness.
  var example = "this is broken"
```

But that's an already-broken edge case, while this is common:

```jade
style(type='text/css', data-example="There's space in here!")
  /* this block would get passed over because the tag had white space before the newline */
```

In lieu of a more robust rule, we'll just let the edge case fall beneath the cracks.