he never finishes his code example until the end
exemple:
<!doctype html>
<html lang="en">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css" integrity="sha384-9aIt2nRpC12Uk9gS9baDl411NQApFmC26EwAOH8WgZl5MYYxFfc+NcPb1dKGj7Sk" crossorigin="anonymous">
<title>Gestion des courses</title>
</head>
<body>
<div class="container mt-5">
<h1>Gestion des courses</h1>
<form>
<div class="form-group">
<label for="itemInput">Article</label>
<input type="text" class="form-control" id="itemInput" placeholder="Entrez l'article à ajouter">
</div>
<button type="submit" class="btn btn-primary" id="addButton">Ajouter</button>
<button type="button" class="btn btn-danger" id="removeButton">Supprimer</button>
</form>
<ul class="list-group mt-3" id="shoppingList">
<!-- Les articles de la liste de courses seront ajoutés ici en utilisant JavaScript -->
</ul>
</div>
<!-- Optional JavaScript -->
<!-- jQuery first, then Popper.js, then Bootstrap JS -->
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/@popperjs/core@2.16.6/dist/umd/popper.min.js" integrity="sha384-wHAiFfRlMFy6i5SRaxvfOCifBUQy1xHdJ/yoi7FRNXMRBu5WHdZYu1hA6ZOblgut" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js" integrity="sha384-OgVRvuATP1z7JjHLkuOU7Xw704+h835Lr+6QL9UvYjZE3