Empty Datasette([]) list is no longer required

docs/testing_plugins.rst

@@ -15,7 +15,7 @@ If you use the template described in :ref:`writing_plugins_cookiecutter` your pl
 
     @pytest.mark.asyncio
     async def test_plugin_is_installed():
-        datasette = Datasette([], memory=True)
+        datasette = Datasette(memory=True)
         response = await datasette.client.get("/-/plugins.json")
         assert response.status_code == 200
         installed_plugins = {p["name"] for p in response.json()}