Feat: add new Markdown parser (#39800)

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

curriculum/challenges/english/10-coding-interview-prep/rosetta-code/least-common-multiple.md

@@ -5,55 +5,61 @@ challengeType: 5
 forumTopicId: 302301
 ---
 
-## Description
+# --description--
 
-<section id='description'>
+The least common multiple of 12 and 18 is 36, because 12 is a factor (12 × 3 = 36), and 18 is a factor (18 × 2 = 36), and there is no positive integer less than 36 that has both factors. As a special case, if either *m* or *n* is zero, then the least common multiple is zero. One way to calculate the least common multiple is to iterate all the multiples of *m*, until you find one that is also a multiple of *n*. If you already have *gcd* for [greatest common divisor](<https://rosettacode.org/wiki/greatest common divisor>), then this formula calculates *lcm*. ( \\operatorname{lcm}(m, n) = \\frac{|m \\times n|}{\\operatorname{gcd}(m, n)} )
 
-The least common multiple of 12 and 18 is 36, because 12 is a factor (12 &times; 3 = 36), and 18 is a factor (18 &times; 2 = 36), and there is no positive integer less than 36 that has both factors. As a special case, if either <i>m</i> or <i>n</i> is zero, then the least common multiple is zero.
-One way to calculate the least common multiple is to iterate all the multiples of <i>m</i>, until you find one that is also a multiple of <i>n</i>.
-If you already have <i>gcd</i> for <a href="https://rosettacode.org/wiki/greatest common divisor" target="_blank">greatest common divisor</a>, then this formula calculates <i>lcm</i>.
-\( \operatorname{lcm}(m, n) = \frac{|m \times n|}{\operatorname{gcd}(m, n)} \)
+# --instructions--
 
-</section>
+Compute the least common multiple of an array of integers. Given *m* and *n*, the least common multiple is the smallest positive integer that has both *m* and *n* as factors.
 
-## Instructions
+# --hints--
 
-<section id='instructions'>
+`LCM` should be a function.
 
-Compute the least common multiple of an array of integers.
-Given <i>m</i> and <i>n</i>, the least common multiple is the smallest positive integer that has both <i>m</i> and <i>n</i> as factors.
-
-</section>
-
-## Tests
-
-<section id='tests'>
-
-```yml
-tests:
-  - text: <code>LCM</code> should be a function.
-    testString: assert(typeof LCM == 'function');
-  - text: <code>LCM([2, 4, 8])</code> should return a number.
-    testString: assert(typeof LCM([2, 4, 8]) == 'number');
-  - text: <code>LCM([2, 4, 8])</code> should return <code>8</code>.
-    testString: assert.equal(LCM([2, 4, 8]), 8);
-  - text: <code>LCM([4, 8, 12])</code> should return <code>24</code>.
-    testString: assert.equal(LCM([4, 8, 12]), 24);
-  - text: <code>LCM([3, 4, 5, 12, 40])</code> should return <code>120</code>.
-    testString: assert.equal(LCM([3, 4, 5, 12, 40]), 120);
-  - text: <code>LCM([11, 33, 90])</code> should return <code>990</code>.
-    testString: assert.equal(LCM([11, 33, 90]), 990);
-  - text: <code>LCM([-50, 25, -45, -18, 90, 447])</code> should return <code>67050</code>.
-    testString: assert.equal(LCM([-50, 25, -45, -18, 90, 447]), 67050);
+```js
+assert(typeof LCM == 'function');
 ```
 
-</section>
+`LCM([2, 4, 8])` should return a number.
 
-## Challenge Seed
+```js
+assert(typeof LCM([2, 4, 8]) == 'number');
+```
 
-<section id='challengeSeed'>
+`LCM([2, 4, 8])` should return `8`.
 
-<div id='js-seed'>
+```js
+assert.equal(LCM([2, 4, 8]), 8);
+```
+
+`LCM([4, 8, 12])` should return `24`.
+
+```js
+assert.equal(LCM([4, 8, 12]), 24);
+```
+
+`LCM([3, 4, 5, 12, 40])` should return `120`.
+
+```js
+assert.equal(LCM([3, 4, 5, 12, 40]), 120);
+```
+
+`LCM([11, 33, 90])` should return `990`.
+
+```js
+assert.equal(LCM([11, 33, 90]), 990);
+```
+
+`LCM([-50, 25, -45, -18, 90, 447])` should return `67050`.
+
+```js
+assert.equal(LCM([-50, 25, -45, -18, 90, 447]), 67050);
+```
+
+# --seed--
+
+## --seed-contents--
 
 ```js
 function LCM(A) {
@@ -61,12 +67,7 @@ function LCM(A) {
 }
 ```
 
-</div>
-</section>
-
-## Solution
-
-<section id='solution'>
+# --solutions--
 
 ```js
 function LCM(A) {
@@ -83,5 +84,3 @@ function LCM(A) {
   return a;
 }
 ```
-
-</section>