Skip sorting on empty search string
Skip sorting on empty search string

For the empty query, sorting can be the slowest part of the search.
Since the empty query gives no scores, and we've now made our sort
stable, in this case we can simply skip sorting.

A sort of 250000 entries took about ~10ms on my laptop, which is not a
huge amount. However it's not 0 and is free to skip.

jhawthorn/fzy,jhawthorn/fzy,jhawthorn/fzy