Reactjs section and its course added (#6400)

* Update free-courses-fa_IR.md

A new section for Reactjs under Javascript was added, also a new youtube complete tutorial for Reactjs is added.

* Apply suggestions from code review

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

courses/free-courses-fa_IR.md

@@ -2,9 +2,10 @@
 
 * [Blockchain](#blockchain)
 * [C, C++](#c)
-* [Git](#Git)
+* [Git](#git)
 * [Java](#java)
 * [JavaScript](#javascript)
+  * [React](#react)
 * [Kotlin](#kotlin)
 * [Linux](#linux)
 * [Machine Learning](#machine-learning)
@@ -52,6 +53,11 @@
 * [دوره اموزشی جاوا اسکریپت از صفر](https://www.youtube.com/playlist?list=PLAt10Vana3Yctuu576LSxK6AiskBiWgOF) - Silicium
 
 
+#### React
+
+* [ری اکت جی اس ۲۰۲۰](https://www.youtube.com/playlist?list=PL3Y-E4YSE4wZpWH8CXwPBI1F13KhkIDEx) - Amir Azimi
+
+
 ### Kotlin
 
 * [آموزش کامل برنامه نویسی با کاتلین](https://www.youtube.com/watch?v=SwhXvaXx078) - Amirahmad Adibi