Add Resource on Emacs editor (#4189)

* Add a textbook introducing emacs driven text editing

* Add a newline to match formatting

* Change ordering of tutorials to be alphabetical

free-programming-books.md

@@ -1244,6 +1244,7 @@ Kerridge (PDF) (email address *requested*, not required)
 ### Emacs
 
 * [An Introduction to Programming in Emacs Lisp, 3rd Edition](https://www.gnu.org/software/emacs/manual/html_node/eintr/index.html)
+* [Emacs for the Modern World](https://www.finseth.com/craft/) (HTML)
 * [GNU Emacs Lisp Reference Manual](http://www.gnu.org/software/emacs/manual/elisp.html)
 * [GNU Emacs Manual](https://www.gnu.org/software/emacs/manual/pdf/emacs.pdf) (PDF)