testbed: quick check for storage window

testbed/system/imgui_system.cpp

@@ -6,9 +6,13 @@
 namespace testbed {
 
 void imgui_system(const entt::registry &registry) {
-    ImGui::Begin("Davey");
+    ImGui::Begin("Davey - registry");
     entt::davey(registry);
     ImGui::End();
+
+    ImGui::Begin("Davey - storage");
+    entt::davey(*registry.storage<int>());
+    ImGui::End();
 }
 
 } // namespace testbed