Update snippet descriptions

snippets/generateItems.md

@@ -6,6 +6,7 @@ tags: array,function,intermediate
 Generates an array with the given amount of items, using the given function.
 
 - Use  `Array.from()`  to create an empty array of the specific length, calling `fn` with the index of each newly created element.
+- The callback takes one argument - the index of each element.
 
 ```js
 const generateItems = (n, fn) => Array.from({ length: n }, (_, i) => fn(i));