style guide fix Array().fill -> Array.from()

snippets/initialize2DArray.md

@@ -6,9 +6,7 @@ Use `Array.map()` to generate h rows where each is a new array of size w initial
 
 ```js
 const initialize2DArray = (w, h, val = null) =>
-  Array(h)
-    .fill()
-    .map(() => Array(w).fill(val));
+  Array.from({ length: h }).map(() => Array(w).fill(val));
 ```
 
 ```js