= New Features

* Set instances are now supported as matchers by default, as Set
  will be a core class in Ruby 4.0. A Set matcher operates
  similarly to an array matcher if all of the array elements are
  strings, with the difference that the Set matcher will perform
  better for large numbers of elements, since it will look for
  a matching entry in the set, instead of iterating over the
  elements of the set.
