`raise` is not source mapped

[JPDuchesne]

Raising with raise results in ? line number, i.e.

transform!(RSpock::AST::Transformation)
class MyTest < Minitest::Test
  extend ASTTransform::Declarative

  test "wrong line number" do
    Expect
    1 + 2 == 3
    raise
  end
end

Raising with a parameter works OK:

transform!(RSpock::AST::Transformation)
class MyTest < Minitest::Test
  extend ASTTransform::Declarative

  test "wrong line number" do
    Expect
    1 + 2 == 3
    raise("runtime error")
  end
end