fix: homogenize markdown across files using markdownlint rules (#6988)

* chore: homogenize C# table of content anchor (`#c-sharp` to `#csharp`)

* format: homogenize c# category title

right markdown escape instead of use HTML entities

* lint: fix `MD012/no-multiple-blanks` rule

Multiple consecutive blank lines [Expected: 2; Actual: 3]

* lint: fix `MD039/no-space-in-links`

Spaces inside link text

* lint: fix `MD009/no-trailing-spaces` rule

Trailing spaces [Expected: 0 or 4; Actual: 1]
Trailing spaces [Expected: 0 or 4; Actual: 2]

* lint: fix `MD006/ul-start-left` rule

* format: remove extra spaces between note tokens

* spell: fix lint `MD044/proper-names` rule

- HTML
- JavaScript
- YouTube

* spell: normalize to the most common `Index` heading

* lint: fix `MD007/ul-indent` rule

Unordered list indentation [Expected: 4; Actual: 2]

* format: escape pipes `|` from resources text

addresses #5176

* add Hesham Asem courses about machine and deep learning and nlp

* Expand the name of nlp section

* Change the order

* Revert "spell: normalize to the most common `Index` heading"

This reverts commit 4d6a74e7d7.

Co-authored-by: AhmedElTabarani <eltabaraniahmed@gmail.com>

more/free-programming-playgrounds.md

@@ -19,7 +19,7 @@
 * [Ionic](#ionic)
 * [Java](#java)
 * [JavaScript](#javascript)
-  * [AngularJS](#angularjs)
+    * [AngularJS](#angularjs)
 * [Kotlin](#kotlin)
 * [Kubernetes](#kubernetes)
 * [.Net](#dotnet)
@@ -43,7 +43,7 @@
 * [Svelte](#svelte)
 * [Swift](#swift)
 * [TypeScript](#typescript)
-  * [Angular](#angular)
+    * [Angular](#angular)
 * [V](#v)