Adds failing test

[cspotcode]

Selector references don't always insert spaces when they should, assuming that I'm understanding the spec correctly.

Selectors that don't have any sort of explicit reference (&, ^[], ../, etc) are given an implicit reference like this:

.foo
  // A selector without an explicit reference...
  .bar
  // ... is implicitly prefixed with `& ` (ampersand and space)
  & .bar

I assume that, since a space character is being specified between .bar and .foo, either explicitly or implicitly, it should be inserted into the rendered selector. This doesn't always happen.

[kizu]

That's an intended behavior, otherwise it would be rather hard to use those selectors without the space combinator, look at this example:

.foo
  & .bar
    ^[0] a^[-1..-1]
      width: 10px

And inserting a space manually when needed is much simpler than removing it. If there'd be a need to programmatically use the exact subselector, it would still be possible to get the space (or its absence) from the selectors().