add break to number case

1-js/02-first-steps/17-javascript-specials/article.md

@@ -213,6 +213,7 @@ let age = prompt('Your age?', 18);
 switch (age) {
   case 18:
     alert("Won't work"); // the result of prompt is a string, not a number
+    break;
 
   case "18":
     alert("This works!");