Snippet format update

To match the starter (for the migration)

snippets/initial.md

@@ -1,4 +1,7 @@
-### initial
+---
+title: initial
+tags: array,beginner
+---
 
 Returns all the elements of an array except the last one.
 
@@ -10,4 +13,4 @@ const initial = arr => arr.slice(0, -1);
 
 ```js
 initial([1, 2, 3]); // [1,2]
-```
+```