Feat: add new Markdown parser (#39800)

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

curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-127-abc-hits.md

@@ -1,48 +1,49 @@
 ---
 id: 5900f3ec1000cf542c50fefe
-challengeType: 5
 title: 'Problem 127: abc-hits'
+challengeType: 5
 forumTopicId: 301754
 ---
 
-## Description
-<section id='description'>
+# --description--
+
 The radical of n, rad(n), is the product of distinct prime factors of n. For example, 504 = 23 × 32 × 7, so rad(504) = 2 × 3 × 7 = 42.
+
 We shall define the triplet of positive integers (a, b, c) to be an abc-hit if:
+
 GCD(a, b) = GCD(a, c) = GCD(b, c) = 1
-a < b
+
+a &lt; b
+
 a + b = c
-rad(abc) < c
+
+rad(abc) &lt; c
+
 For example, (5, 27, 32) is an abc-hit, because:
+
 GCD(5, 27) = GCD(5, 32) = GCD(27, 32) = 1
-5 < 27
+
+5 &lt; 27
+
 5 + 27 = 32
-rad(4320) = 30 < 32
-It turns out that abc-hits are quite rare and there are only thirty-one abc-hits for c < 1000, with ∑c = 12523.
-Find ∑c for c < 120000.
-</section>
 
-## Instructions
-<section id='instructions'>
+rad(4320) = 30 &lt; 32
 
-</section>
+It turns out that abc-hits are quite rare and there are only thirty-one abc-hits for c &lt; 1000, with ∑c = 12523.
 
-## Tests
-<section id='tests'>
+Find ∑c for c &lt; 120000.
 
-```yml
-tests:
-  - text: <code>euler127()</code> should return 18407904.
-    testString: assert.strictEqual(euler127(), 18407904);
+# --hints--
 
+`euler127()` should return 18407904.
+
+```js
+assert.strictEqual(euler127(), 18407904);
 ```
 
-</section>
+# --seed--
 
-## Challenge Seed
-<section id='challengeSeed'>
-
-<div id='js-seed'>
+## --seed-contents--
 
 ```js
 function euler127() {
@@ -53,17 +54,8 @@ function euler127() {
 euler127();
 ```
 
-</div>
-
-
-
-</section>
-
-## Solution
-<section id='solution'>
+# --solutions--
 
 ```js
 // solution required
 ```
-
-</section>