Make nested styles composition possible

[Karibash]

Currently, if you pass an array of style rules to the style function, they are composed by deepmerge.
It would be useful to be able to pass an array to compose even nested styles as shown below.

const className = style({
  '::after': [
    {
      padding: 0,
    },
    {
      margin: 0,
    },
  ],
});