add clarification about forget method return value (#9982)

the wording here is just a little unclear. the first sentence seems to suggest that the `forget()` method does not return anything, even though it does.

you are free to assign the result to a new variable even though you don't need to.

collections.md

@@ -1083,7 +1083,7 @@ The `forget` method removes an item from the collection by its key:
     // []
 
 > [!WARNING]  
-> Unlike most other collection methods, `forget` does not return a new modified collection; it modifies the collection it is called on.
+> Unlike most other collection methods, `forget` does not return a new modified collection; it modifies and returns the collection it is called on.
 
 <a name="method-forpage"></a>
 #### `forPage()` {.collection-method}