Snippet format update

To match the starter (for the migration)

snippets/invertKeyValues.md

@@ -1,4 +1,7 @@
-### invertKeyValues
+---
+title: invertKeyValues
+tags: object,function,intermediate
+---
 
 Inverts the key-value pairs of an object, without mutating it. The corresponding inverted value of each inverted key is an array of keys responsible for generating the inverted value. If a function is supplied, it is applied to each inverted key.
 
@@ -18,4 +21,4 @@ const invertKeyValues = (obj, fn) =>
 ```js
 invertKeyValues({ a: 1, b: 2, c: 1 }); // { 1: [ 'a', 'c' ], 2: [ 'b' ] }
 invertKeyValues({ a: 1, b: 2, c: 1 }, value => 'group' + value); // { group1: [ 'a', 'c' ], group2: [ 'b' ] }
-```
+```