Snippet format update

To match the starter (for the migration)

snippets/luhnCheck.md

@@ -1,4 +1,7 @@
-### luhnCheck
+---
+title: luhnCheck
+tags: math,utility,advanced
+---
 
 Implementation of the [Luhn Algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm) used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers etc.
 
@@ -7,7 +10,6 @@ Use `Array.prototype.splice(0,1)` to obtain the last digit.
 Use `Array.prototype.reduce()` to implement the Luhn Algorithm.
 Return `true` if `sum` is divisible by `10`, `false` otherwise.
 
-
 ```js
 const luhnCheck = num => {
   let arr = (num + '')
@@ -25,4 +27,4 @@ const luhnCheck = num => {
 luhnCheck('4485275742308327'); // true
 luhnCheck(6011329933655299); //  false
 luhnCheck(123456789); // false
-```
+```