Update free-programming-books-langs.md (#9450)

* Update free-programming-books-langs.md

The book is not free. Only a sample of it is free.

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

Co-authored-by: Leithen <lcrider@cvent.com>

---------

Co-authored-by: Leithen <lcrider@cvent.com>

books/free-programming-books-langs.md

@@ -528,7 +528,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Essential C++](https://www.programming-books.io/essential/cpp/) - Krzysztof Kowalczyk, StackOverflow Contributors
 * [Financial Numerical Recipes in C++](https://ba-odegaard.no/gcc_prog/recipes/) - Bernt Arne Ødegaard (PDF)
 * [Fundamentals of C++ Programming](https://web.archive.org/web/20191005170118/https://python.cs.southern.edu/cppbook/progcpp.pdf) - Richard L. Halterman (PDF) *(:card_file_box: archived)*
-* [Game Programming Patterns](http://gameprogrammingpatterns.com)
+* [Game Programming Patterns](http://gameprogrammingpatterns.com/contents.html) (HTML)
 * [Google's C++ Style Guide](https://google.github.io/styleguide/cppguide.html)
 * [Hands-On System Programming with C++](https://www.packtpub.com/free-ebook/hands-on-system-programming-with-c/9781789137880) - Dr. Rian Quinn (Packt account *required*)
 * [How to make an Operating System](https://samypesse.gitbook.io/how-to-create-an-operating-system/) - Samy Pesse