Remove "Professional Assembly Language" (#6612)

The book is non-free.

books/free-programming-books-langs.md

@@ -323,7 +323,6 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Assemblers And Loaders (1993)](http://www.davidsalomon.name/assem.advertis/asl.pdf) - David Salomon (PDF)
 * [Assembly Language Succinctly](https://www.syncfusion.com/succinctly-free-ebooks/assemblylanguage) - Christopher Rose, Syncfusion Inc. (HTML, PDF, EPUB, Kindle)
 * [PC Assembly Language](http://pacman128.github.io/pcasm/) - P. A. Carter
-* [Professional Assembly Language](https://web.archive.org/web/20170329045538/http://blog.hit.edu.cn:80/jsx/upload/AT%EF%BC%86TAssemblyLanguage.pdf) (PDF)
 * [Programming from the Ground Up](https://download-mirror.savannah.gnu.org/releases/pgubook/ProgrammingGroundUp-1-0-booksize.pdf) - Jonathan Bartlett (PDF)
 * [Ralf Brown's Interrupt List](http://www.ctyme.com/rbrown.htm)
 * [Run Down On x86 Intel Assembly Course](https://github.com/Ret2LC/x86-assembly) - Ret2LC