Rename `sort_choices` to `choicecmp`
Rename `sort_choices` to `choicecmp`

Inspired by `strcmp`, this clarifies that the function is used as a
comparison function.

calleerlandsson/pick,prahlad37/pick,thoughtbot/pick,calleerlandsson/pick,DBOTW/pick,thoughtbot/pick,DBOTW/pick,prahlad37/pick,prahlad37/pick,thoughtbot/pick,thoughtbot/pick,calleerlandsson/pick,prahlad37/pick,DBOTW/pick