Feat: add new Markdown parser (#39800)

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

curriculum/challenges/english/10-coding-interview-prep/rosetta-code/hofstadter-q-sequence.md

@@ -1,48 +1,70 @@
 ---
-title: Hofstadter Q sequence
 id: 59637c4d89f6786115efd814
+title: Hofstadter Q sequence
 challengeType: 5
 forumTopicId: 302287
 ---
 
-## Description
-<section id='description'>
-The <a href="https://en.wikipedia.org/wiki/Hofstadter_sequence#Hofstadter_Q_sequence" title="wp: Hofstadter_sequence#Hofstadter_Q_sequence" target="_blank">Hofstadter Q sequence</a> is defined as:
-<span style="left-margin: 2em;">$Q(1)=Q(2)=1, \\ Q(n)=Q\big(n-Q(n-1)\big)+Q\big(n-Q(n-2)), \quad n>2.$</span>
-It is defined like the <a href="https://rosettacode.org/wiki/Fibonacci sequence" title="Fibonacci sequence" target="_blank">Fibonacci sequence</a>, but whereas the next term in the Fibonacci sequence is the sum of the previous two terms, in the Q sequence the previous two terms tell you how far to go back in the Q sequence to find the two numbers to sum to make the next term of the sequence.
-</section>
+# --description--
 
-## Instructions
-<section id='instructions'>
-Implement the Hofstadter Q Sequence equation as a function. The function should accept number, <code>n</code>, and return an integer.
-</section>
+The [Hofstadter Q sequence](https://en.wikipedia.org/wiki/Hofstadter_sequence#Hofstadter_Q_sequence "wp: Hofstadter_sequence#Hofstadter_Q_sequence") is defined as:
 
-## Tests
-<section id='tests'>
+$Q(1)=Q(2)=1, \\\\ Q(n)=Q\\big(n-Q(n-1)\\big)+Q\\big(n-Q(n-2)), \\quad n>2.$
 
-```yml
-tests:
-  - text: <code>hofstadterQ</code> should be a function.
-    testString: assert(typeof hofstadterQ === 'function');
-  - text: <code>hofstadterQ()</code> should return <code>integer</code>
-    testString: assert(Number.isInteger(hofstadterQ(1000)));
-  - text: <code>hofstadterQ(1000)</code> should return <code>502</code>
-    testString: assert.equal(hofstadterQ(testCase[0]), res[0]);
-  - text: <code>hofstadterQ(1500)</code> should return <code>755</code>
-    testString: assert.equal(hofstadterQ(testCase[1]), res[1]);
-  - text: <code>hofstadterQ(2000)</code> should return <code>1005</code>
-    testString: assert.equal(hofstadterQ(testCase[2]), res[2]);
-  - text: <code>hofstadterQ(2500)</code> should return <code>1261</code>
-    testString: assert.equal(hofstadterQ(testCase[3]), res[3]);
+It is defined like the [Fibonacci sequence](<https://rosettacode.org/wiki/Fibonacci sequence> "Fibonacci sequence"), but whereas the next term in the Fibonacci sequence is the sum of the previous two terms, in the Q sequence the previous two terms tell you how far to go back in the Q sequence to find the two numbers to sum to make the next term of the sequence.
 
+# --instructions--
+
+Implement the Hofstadter Q Sequence equation as a function. The function should accept number, `n`, and return an integer.
+
+# --hints--
+
+`hofstadterQ` should be a function.
+
+```js
+assert(typeof hofstadterQ === 'function');
 ```
 
-</section>
+`hofstadterQ()` should return `integer`
 
-## Challenge Seed
-<section id='challengeSeed'>
+```js
+assert(Number.isInteger(hofstadterQ(1000)));
+```
 
-<div id='js-seed'>
+`hofstadterQ(1000)` should return `502`
+
+```js
+assert.equal(hofstadterQ(testCase[0]), res[0]);
+```
+
+`hofstadterQ(1500)` should return `755`
+
+```js
+assert.equal(hofstadterQ(testCase[1]), res[1]);
+```
+
+`hofstadterQ(2000)` should return `1005`
+
+```js
+assert.equal(hofstadterQ(testCase[2]), res[2]);
+```
+
+`hofstadterQ(2500)` should return `1261`
+
+```js
+assert.equal(hofstadterQ(testCase[3]), res[3]);
+```
+
+# --seed--
+
+## --after-user-code--
+
+```js
+const testCase = [1000, 1500, 2000, 2500];
+const res = [502, 755, 1005, 1261];
+```
+
+## --seed-contents--
 
 ```js
 function hofstadterQ(n) {
@@ -51,24 +73,7 @@ function hofstadterQ(n) {
 }
 ```
 
-</div>
-
-
-### After Test
-<div id='js-teardown'>
-
-```js
-const testCase = [1000, 1500, 2000, 2500];
-const res = [502, 755, 1005, 1261];
-```
-
-</div>
-
-</section>
-
-## Solution
-<section id='solution'>
-
+# --solutions--
 
 ```js
 function hofstadterQ (n) {
@@ -83,7 +88,4 @@ function hofstadterQ (n) {
   };
   return Q(n);
 }
-
 ```
-
-</section>