Add CC BY-SA License to "CSS Notes for Professionals" (#11696)

* Add GPL-3.0-or-later license to 'Matters Computational' book entry

* Update free-programming-books-langs.md with new resources and licenses

* Add specific changes for second pull request

* Update books/free-programming-books-langs.md

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

* Added License in HTML book

* Add license information to books

---------

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

books/free-programming-books-langs.md

@@ -947,7 +947,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Canvassing](https://web.archive.org/web/20160505010319/http://learnjs.io/canvassing/read/) *(:card_file_box: archived)*
 * [Code Guide: Standards for developing flexible, durable, and sustainable HTML and CSS](http://mdo.github.io/code-guide/) - Mark Otto
 * [CSS Animation 101](https://github.com/cssanimation/css-animation-101)
-* [CSS Notes for Professionals](http://goalkicker.com/CSSBook) - Compiled from StackOverflow Documentation (PDF)
+* [CSS Notes for Professionals](http://goalkicker.com/CSSBook) - Compiled from StackOverflow Documentation (PDF) (CC BY-SA)
 * [CSS Optimization Basics](https://github.com/frontenddogma/css-optimization-basics) – Jens Oliver Meiert
 * [CSS Transition vs CSS animation](https://www.freecodecamp.org/news/css-transition-vs-css-animation-handbook/) - Oluwatobi Sofela
 * [Dive Into HTML5](http://diveinto.html5doctor.com) - Mark Pilgrim ([PDF](http://mislav.net/2011/10/dive-into-html5/))