Andrew d552e20096 create new "empty" variant
this will generate classes like the following:

```css
.empty\:hidden:empty {
  display: none
}
```
2021-01-06 12:19:21 -06:00
..
2020-10-19 20:18:53 -04:00
2021-01-06 12:19:21 -06:00
2020-12-02 15:45:04 -05:00
2020-10-16 15:39:44 -04:00
2020-10-16 15:39:44 -04:00
2020-11-15 16:13:48 -05:00
2020-11-16 14:13:49 -05:00