chore: enabled MD040 lint rule (#47853)

* enabled `MD040` lint rule

* fix: lint errors

* using `markup` instead of `text`

curriculum/challenges/.markdownlint.yaml

@@ -5,7 +5,7 @@ MD022: false   # headings don't need surrounding by newlines
 MD025: false   # headings are used as markers by the parser
 MD031: true    # fenced blocks do need surrounding by newlines
 MD033: false   # inline html is required
-MD040: false   # TODO: enable this when the challenges have been fixed
+MD040: true    # fenced code blocks should have a language specified
 MD034: false   # allow bare-URLs
 MD036: false   # TODO: **Example** is the main offender, should that be a heading?
 whitespace: false  # extra whitespace is ignored, so we don't enforce it.

curriculum/challenges/english/08-data-analysis-with-python/data-analysis-with-python-course/pandas-introduction.md

@@ -38,7 +38,7 @@ print(certificates_earned)
 
 ## --answers--
 
-```
+```markup
 Tom      8
 Kris     2
 Ahmad    5
@@ -48,7 +48,7 @@ dtype: int64
 
 ---
 
-```
+```markup
 Kris     2
 Ahmad    5
 Beau     6
@@ -58,7 +58,7 @@ dtype: int64
 
 ---
 
-```
+```markup
 Tom      8
 Kris     2
 Ahmad    5

curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-148-exploring-pascals-triangle.md

@@ -10,7 +10,7 @@ dashedName: problem-148-exploring-pascals-triangle
 
 We can easily verify that none of the entries in the first seven rows of Pascal's triangle are divisible by 7:
 
-```
+```markup
             1
           1   1
         1   2   1

curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-191-prize-strings.md

@@ -14,7 +14,7 @@ During an n-day period a trinary string is formed for each child consisting of L
 
 Although there are eighty-one trinary strings for a 4-day period that can be formed, exactly forty-three strings would lead to a prize:
 
-```
+```markup
 OOOO OOOA OOOL OOAO OOAA OOAL OOLO OOLA OAOO OAOA
 OAOL OAAO OAAL OALO OALA OLOO OLOA OLAO OLAA AOOO
 AOOA AOOL AOAO AOAA AOAL AOLO AOLA AAOO AAOA AAOL

curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-66-diophantine-equation.md

@@ -40,25 +40,25 @@ assert(typeof diophantineEquation(7) === 'number');
 
 `diophantineEquation(7)` should return `5`.
 
-```
+```js
 assert.strictEqual(diophantineEquation(7), 5);
 ```
 
 `diophantineEquation(100)` should return `61`.
 
-```
+```js
 assert.strictEqual(diophantineEquation(100), 61);
 ```
 
 `diophantineEquation(409)` should return `409`.
 
-```
+```js
 assert.strictEqual(diophantineEquation(409), 409);
 ```
 
 `diophantineEquation(500)` should return `421`.
 
-```
+```js
 assert.strictEqual(diophantineEquation(500), 421);
 ```
 

curriculum/challenges/english/14-responsive-web-design-22/learn-css-colors-by-building-a-set-of-colored-markers/619b7c3c83de403126b69c1e.md

@@ -9,7 +9,7 @@ dashedName: step-47
 
 You may already be familiar with decimal, or base 10 values, which go from 0 - 9. Hexadecimal, or base 16 values, go from 0 - 9, then A - F:
 
-```
+```js
 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F
 ```
 

curriculum/challenges/english/14-responsive-web-design-22/learn-responsive-web-design-by-building-a-piano/612ec19d5268da7074941f84.md

@@ -11,7 +11,7 @@ Logical operators can be used to construct more complex media queries. The `and`
 
 For example, a media query that targets a display width between 500px and 1000px would be:
 
-```
+```css
 @media (min-width: 500px) and (max-width: 1000px){
 
 }

curriculum/challenges/english/14-responsive-web-design-22/learn-typography-by-building-a-nutrition-label/615f905fbd1017a65ca224eb.md

@@ -11,7 +11,7 @@ Add a medium divider after your `.daily-value` element. Below that new divider,
 
 Give the `p` element the following text:
 
-```
+```markup
 * The % Daily Value (DV) tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
 ```
 

curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-javascript-by-building-a-role-playing-game/62a2401b9842721796b72850.md

@@ -9,7 +9,7 @@ dashedName: step-7
 
 Give your `#text` element the following text:
 
-```
+```markup
 Welcome to Dragon Repeller. You must defeat the dragon that is preventing people from leaving the town. 
 You are in the town square. Where do you want to go? Use the buttons above.
 ```