Branch main veer (#10658)

* add in free-courses-en.md

* Add Course MySQL Free

* add play ground in HTML CSS of free-programming-playgrounds

* add play ground in HTML CSS of free-programming-playground

* Update free-programming-playgrounds.md

* Update courses/free-courses-en.md

---------

Co-authored-by: Eric Hellman <eric@hellman.net>

more/free-programming-playgrounds.md

@@ -192,6 +192,7 @@
 * [Learn advanced html and css](https://www.theodinproject.com/paths/full-stack-javascript/courses/advanced-html-and-css) - The Odin Project
 * [Learn Intermediate html and css](https://www.theodinproject.com/paths/full-stack-javascript/courses/intermediate-html-and-css) - The Odin Project
 * [LiveCode](https://livecodes.io) - LiveCode
+* [Play Code](https://playcode.io)
 * [SoloLearn](https://code.sololearn.com/web#css)
 * [Tailwind Play](https://play.tailwindcss.com)