updaging step 3 docs

step1-03/demo/README.md

@@ -13,6 +13,7 @@ This demo starts off with a few elements already in place. Let's walk through wh
 - **addTodo()** - This is the primary logic of our todo app. Here's how the lines break down.
   1. `todo` is set to equal the first todo item
   2. `newTodo` is a clone of todo. Passing true means it is a deep clone, so we get the todo's children as well. Cloning does not duplicate the DOM node. We'll need to insert it in step 4
+     > Note that this approach is very fragile, as it requires a node todo node to always be present
   3. We set the innerText of the `<span class='title'>` to the value returned from getTodoText
      > Note that if we left off the `()` we'd actually be assigning innerText to the 'function' instead of the function return
   4. Insert our new todo into the todo's parent (the `ul`), before our reference todo. [insertBefore](https://developer.mozilla.org/en-US/docs/Web/API/Node/insertBefore)