Feat: add new Markdown parser (#39800)

and change all the challenges to new `md` format.

curriculum/challenges/english/10-coding-interview-prep/rosetta-code/happy-numbers.md

@@ -1,61 +1,103 @@
 ---
-title: Happy numbers
 id: 594810f028c0303b75339ad1
+title: Happy numbers
 challengeType: 5
 forumTopicId: 302280
 ---
 
-## Description
-<section id='description'>
-A <a href="https://en.wikipedia.org/wiki/Happy_number" target="_blank">happy number</a> is defined by the following process:
-Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals <code>1</code> (where it will stay), or it loops endlessly in a cycle which does not include <code>1</code>. Those numbers for which this process ends in <code>1</code> are happy numbers, while those that do not end in <code>1</code> are unhappy numbers.
-</section>
+# --description--
+
+A [happy number](https://en.wikipedia.org/wiki/Happy_number) is defined by the following process:
+
+Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals `1` (where it will stay), or it loops endlessly in a cycle which does not include `1`. Those numbers for which this process ends in `1` are happy numbers, while those that do not end in `1` are unhappy numbers.
+
+# --instructions--
 
-## Instructions
-<section id='instructions'>
 Implement a function that returns true if the number is happy, or false if not.
-</section>
 
-## Tests
-<section id='tests'>
+# --hints--
 
-```yml
-tests:
-  - text: <code>happy</code> should be a function.
-    testString: assert(typeof happy === 'function');
-  - text: <code>happy(1)</code> should return a boolean.
-    testString: assert(typeof happy(1) === 'boolean');
-  - text: <code>happy(1)</code> should return true.
-    testString: assert(happy(1));
-  - text: <code>happy(2)</code> should return false.
-    testString: assert(!happy(2));
-  - text: <code>happy(7)</code> should return true.
-    testString: assert(happy(7));
-  - text: <code>happy(10)</code> should return true.
-    testString: assert(happy(10));
-  - text: <code>happy(13)</code> should return true.
-    testString: assert(happy(13));
-  - text: <code>happy(19)</code> should return true.
-    testString: assert(happy(19));
-  - text: <code>happy(23)</code> should return true.
-    testString: assert(happy(23));
-  - text: <code>happy(28)</code> should return true.
-    testString: assert(happy(28));
-  - text: <code>happy(31)</code> should return true.
-    testString: assert(happy(31));
-  - text: <code>happy(32)</code> should return true:.
-    testString: assert(happy(32));
-  - text: <code>happy(33)</code> should return false.
-    testString: assert(!happy(33));
+`happy` should be a function.
 
+```js
+assert(typeof happy === 'function');
 ```
 
-</section>
+`happy(1)` should return a boolean.
 
-## Challenge Seed
-<section id='challengeSeed'>
+```js
+assert(typeof happy(1) === 'boolean');
+```
 
-<div id='js-seed'>
+`happy(1)` should return true.
+
+```js
+assert(happy(1));
+```
+
+`happy(2)` should return false.
+
+```js
+assert(!happy(2));
+```
+
+`happy(7)` should return true.
+
+```js
+assert(happy(7));
+```
+
+`happy(10)` should return true.
+
+```js
+assert(happy(10));
+```
+
+`happy(13)` should return true.
+
+```js
+assert(happy(13));
+```
+
+`happy(19)` should return true.
+
+```js
+assert(happy(19));
+```
+
+`happy(23)` should return true.
+
+```js
+assert(happy(23));
+```
+
+`happy(28)` should return true.
+
+```js
+assert(happy(28));
+```
+
+`happy(31)` should return true.
+
+```js
+assert(happy(31));
+```
+
+`happy(32)` should return true:.
+
+```js
+assert(happy(32));
+```
+
+`happy(33)` should return false.
+
+```js
+assert(!happy(33));
+```
+
+# --seed--
+
+## --seed-contents--
 
 ```js
 function happy(number) {
@@ -63,15 +105,7 @@ function happy(number) {
 }
 ```
 
-</div>
-
-
-
-</section>
-
-## Solution
-<section id='solution'>
-
+# --solutions--
 
 ```js
 function happy (number) {
@@ -91,7 +125,4 @@ function happy (number) {
   }
   return (number === 1);
 }
-
 ```
-
-</section>