Add React cheatsheet (#5580)

* Add React cheatsheet

Add React cheatsheet and fix some misunderstandings. I think it would be better not to mix JavaScript or Python with HTML.

* update line

* fix issue

* fix issue

* Fix alphabetical order

Co-authored-by: ImVector <59611597+LuigiImVector@users.noreply.github.com>

* Update to HTML

Co-authored-by: ImVector <59611597+LuigiImVector@users.noreply.github.com>

more/free-programming-cheatsheets.md

@@ -12,6 +12,7 @@
 * [Java](#java)
 * [JavaScript](#javascript)
   * [jQuery](#jquery)
+  * [React.js](#reactjs)
   * [Vue.js](#vuejs)
 * [Kubernetes](#kubernetes)
 * [Language Translations](#language-translations)
@@ -104,6 +105,11 @@
 * [jQuery CheatSheet](https://htmlcheatsheet.com/jquery/) (HTML)
 
 
+#### React.js
+
+* [React Cheatsheet](https://www.codecademy.com/learn/react-101/modules/react-101-jsx-u/cheatsheet) - Codecademy (HTML)
+
+
 #### Vue.js
 
 * [Vue Essential Cheatsheet](https://www.vuemastery.com/pdf/Vue-Essentials-Cheat-Sheet.pdf) - Vue Mastery (PDF)