Snippet format update

To match the starter (for the migration)

snippets/intersectionBy.md

@@ -1,4 +1,7 @@
-### intersectionBy
+---
+title: intersectionBy
+tags: array,function,intermediate
+---
 
 Returns a list of elements that exist in both arrays, after applying the provided function to each array element of both.
 
@@ -13,4 +16,4 @@ const intersectionBy = (a, b, fn) => {
 
 ```js
 intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [2.1]
-```
+```