Type that is used as the return type of the pending method in class
Suite, which always completes abruptly with a
TestPendingException.
This type is used primarily to facilitate the is (pending) syntax of
traits FlatSpec and WordSpec, as well the
is (pending) or (pending) syntax of several traits
in the org.scalatest.fixturepackage. Because the pending
method in Suite always completes abruptly with an exception, its
type would be inferred to be Nothing, which is a relatively common
type. To make sure syntax like is (pending) only works with
method pending, it is helpful to have a specially named
"Nothing" type.