Update site/content/tutorial/02-reactivity/04-updating-arrays-and-objects/text.md

Co-authored-by: Ben McCann <322311+benmccann@users.noreply.github.com>

site/content/tutorial/02-reactivity/04-updating-arrays-and-objects/text.md

@@ -23,7 +23,7 @@ function addNumber() {
 }
 ```
 
-The same rule applies to array methods such as `pop`, `shift`, `splice` and to objects methods such as `Map.set`.
+The same rule applies to array methods such as `pop`, `shift`, and `splice` and to objects methods such as `Map.set`, `Set.add`, etc.
 
 Assignments to *properties* of arrays and objects — e.g. `obj.foo += 1` or `array[i] = x` — work the same way as assignments to the values themselves.