Add FrontEnd Masters Guides (#6936)

* Add `Front-End Developer Handbook 2016`

* Add `Front-End Developer Handbook 2017`

* Add `Front-End Developer Handbook 2018`

* Add `Front-End Developer Handbook 2019`

Resolves #6931

* Written by Cody Lindley

* Add `JavaScript (ES2015+) Enlightenment`

* lint: alphabetize-lists

* format: Complete authoring of `React Enlightenment`

* only one link is enough, it said the boss

* delete `sponsored by` author: `Frontend Masters`

books/free-programming-books-langs.md

@@ -1094,10 +1094,10 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Exploring ES6](http://exploringjs.com/es6/) - Dr. Axel Rauschmayer (HTML)
 * [Google JavaScript Style Guide](https://google.github.io/styleguide/javascriptguide.xml) - Aaron Whyte, Bob Jervis, Dan Pupius, Erik Arvidsson, Fritz Schneider, & Robby Walker (HTML)
 * [Human JavaScript](http://read.humanjavascript.com/ch01-introduction.html) - Henrik Joreteg (HTML)
+* [JavaScript (ES2015+) Enlightenment](https://frontendmasters.com/guides/javascript-enlightenment/) - Cody Lindley (HTML)
 * [JavaScript Allongé](https://leanpub.com/javascript-allonge/read) - Reginald Braithwaite (HTML)
 * [JavaScript Bible](http://media.wiley.com/product_ancillary/28/07645334/DOWNLOAD/all.pdf) - Danny Goodman (PDF)
 * [JavaScript Challenges Book](https://tcorral.github.io/javascript-challenges-book/) - Tomás Corral Casas (HTML)
-* [JavaScript Enlightenment](http://www.javascriptenlightenment.com) - Cody Lindley (HTML)
 * [JavaScript ES6 and beyond](https://github.com/AlbertoMontalesi/JavaScript-es6-and-beyond-ebook) - Alberto Montalesi (PDF, epub)
 * [JavaScript For Cats](http://jsforcats.com) - Maxwell Ogden (HTML)
 * [JavaScript for Impatient Programmers (ES2020 edition)](https://exploringjs.com/impatient-js/toc.html) - Dr. Axel Rauschmayer (HTML)
@@ -1285,7 +1285,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [Learning React.js: Getting Started and Concepts](https://scotch.io/tutorials/learning-react-getting-started-and-concepts)
 * [React-Bits](https://github.com/vasanthk/react-bits)
 * [React Book, your beginner guide to React](https://github.com/softchris/react-book/) - Chris Noring
-* [React Enlightenment](https://www.reactenlightenment.com)
+* [React Enlightenment](https://www.reactenlightenment.com) - Cody Lindley (HTML)
 * [React In-depth: An exploration of UI development](https://developmentarc.gitbooks.io/react-indepth/content/)
 * [React in patterns](https://krasimir.gitbooks.io/react-in-patterns/content) - Krasimir Tsonev
 * [React JS Notes for Professionals](https://goalkicker.com/ReactJSBook/) - Compiled from StackOverflow Documentation (PDF)

books/free-programming-books-subjects.md

@@ -532,6 +532,10 @@ Books that cover a specific programming language can be found in the  [BY PROGRA
 * [Encyclopedia of Human Computer Interaction 2nd Edition](https://www.interaction-design.org/literature/book/the-encyclopedia-of-human-computer-interaction-2nd-ed)
 * [Essential Image Optimization](https://images.guide) - Addy Osmani
 * [Foundations of Programming](https://openmymind.net/FoundationsOfProgramming.pdf) - Karl Seguin (PDF)
+* [Front-End Developer Handbook 2016](https://frontendmasters.com/guides/front-end-handbook/2016/) - Cody Lindley (HTML)
+* [Front-End Developer Handbook 2017](https://frontendmasters.com/guides/front-end-handbook/2017/) - Cody Lindley (HTML)
+* [Front-End Developer Handbook 2018](https://frontendmasters.com/guides/front-end-handbook/2018/) - Cody Lindley (HTML)
+* [Front-End Developer Handbook 2019](https://frontendmasters.com/guides/front-end-handbook/2019/) - Cody Lindley (HTML)
 * [Getting Real](https://basecamp.com/books/getting-real) - Basecamp, 37signals ([HTML](https://basecamp.com/gettingreal), [PDF](https://basecamp.com/gettingreal/getting-real.pdf))
 * [Google Maps API Succinctly](https://www.syncfusion.com/ebooks/google_maps_api_succinctly) - Mark Lewin
 * [Hacknot: Essays on Software Development](http://www.lulu.com/shop/ed-johnson/hacknot-essays-on-software-development/ebook/product-17544641.html) - Ed Johnson