Remove unhelpful example

Not really useful without showing dot access.

lib/koans/03_atoms.ex

@@ -11,14 +11,6 @@ defmodule Atoms do
     assert Atom.to_string(:stringified) == ___
   end
 
-  koan "Atoms are often used as keys, because they're faster than strings" do
-    map = %{name: "Jay"}
-    list = [name: "Jay"]
-
-    assert map[:name] == ___
-    assert list[:name] == ___
-  end
-
   koan "It is surprising to find out that booleans are atoms" do
     assert is_atom(true) == ___
     assert is_atom(false) == ___

test/koans/atoms_koans_test.exs

@@ -6,7 +6,6 @@ defmodule AtomsTests do
     answers = [
       :human,
       {:multiple, [:atomized, "stringified"]},
-      {:multiple, ["Jay", "Jay"]},
       {:multiple, [true, true, true, false]},
       {:multiple, [true, String, "HELLO"]},
       {:multiple, [true, [1,2,3]]},