Added Elisp Programming Book (#11568)

* Added Elisp Programming guide

* Revert "Added Elisp Programming guide"

This reverts commit 79e444697d.

* Added Elisp Programming

* Changed order of links and added blank line

* Changed title from Emacs Programmimg to Elisp Programming

books/free-programming-books-langs.md

@@ -1545,6 +1545,7 @@ Books on general-purpose programming that don't focus on a specific language are
 > :information_source: See also … [IDE and editors](free-programming-books-subjects.md#ide-and-editors)
 
 * [An Introduction to Programming in Emacs Lisp](https://www.gnu.org/software/emacs/manual/eintr.html)
+* [Elisp Programming](https://caiorss.github.io/Emacs-Elisp-Programming/Elisp_Programming.html)
 * [GNU Emacs Lisp Reference Manual](http://www.gnu.org/software/emacs/manual/elisp.html)