Member predicate API::Node::asCall

Gets the call referred to by this API node.

For example:

# API::getTopLevelMember("Foo").getMethod("bar").asCall()
Foo.bar

class Bar < Foo
  def doSomething
    # API::getTopLevelMember("Foo").getInstance().getMethod("baz").asCall()
    baz
  end
end