Change assignment link in DOM_manipulation_and_events.md

Changed the link/anchor under ### Assignment which links to MDNs Active Learning section on DOM manipulation.

Old link/anchor: https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents#active_learning_a_dynamic_shopping_list

New link/anchor: #active_learning_basic_dom_manipulation

Old link linked to the second active learning at MDN, new link links to the first active learning which gives the foundation for the second exercise.

I had problems starting with the second exercise, doing the first before helped me a lot and made the second a lot easier.

If this was intended and the link stays the same I would recommend to write at least a hint to the first active learning or state specifically to start with the shopping list.

foundations/javascript_basics/DOM_manipulation_and_events.md

@@ -422,7 +422,7 @@ You can find a more complete list with explanations of each event on [W3Schools
 
 Manipulating web pages is the primary benefit of the JavaScript language! These techniques are things that you are likely to be messing with *every day* as a front-end developer, so let's practice!
 
-1. Complete [MDN's Active Learning sections on DOM manipulation](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents#active_learning_a_dynamic_shopping_list) to test your skills!
+1. Complete [MDN's Active Learning sections on DOM manipulation](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Manipulating_documents#active_learning_basic_dom_manipulation) to test your skills!
 1. Read the following sections from JavaScript Tutorial's series on the DOM to get a broader idea of how events can be used in your pages. Note that some of the methods like `getElementById` are older and see less use today.
 
    As you read, remember that the general ideas can be applied to any event, not only the ones used in examples - but information specific to a certain event type can always be found by checking documentation.