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>

courses/free-courses-it.md

@@ -8,11 +8,11 @@
 * [C#](#csharp)
 * [C++](#cpp)
 * [Database](#database)
-  * [SQL](#sql)
+    * [SQL](#sql)
 * [Delphi](#delphi)
 * [DevOps](#devops)
 * [Embedded](#embedded)
-  * [Arduino](#arduino)
+    * [Arduino](#arduino)
 * [Generale](#generale)
 * [Java](#java)
 * [JavaScript](#javascript)
@@ -26,12 +26,12 @@
 * [Ruby](#ruby)
 * [Sistemi Informativi](#sistemi-informativi)
 * [Sistemi Operativi](#sistemi-operativi)
-  * [Linux](#linux)
+    * [Linux](#linux)
 * [Strumenti di sviluppo](#strumenti-di-sviluppo)
-  * [Git](#git)
-  * [Maven](#maven)
+    * [Git](#git)
+    * [Maven](#maven)
 * [Web](#web)
-  * [Vue](#vue)
+    * [Vue](#vue)
 * [Workshop](#workshop)