* Adding 5 free Bootstrap courses!

There were only 2 resources for the Bootstrap section, so I built this out with courses from Freecodecamp, YouTube, and Class Central.

* Adding 5 Bootstrap free courses (alphabetized)

Needed to alphabetize them :)

* Fixing YouTube link endpoint + removing "YouTube" specification

Hi @SethiPandi — thanks for the comments and the warm welcome to Hacktoberfest! 🎃 I have done the following from your feedback:
- fixed the YouTube endpoint so it links to the playlist (not the original video)
- Removed YouTube specification from the two resources that are YT videos

Let me know if you need any other changes from me 😊

* Add Vulkan tutorial C++ #3683, check_urls=free-programming-books.md

* Fix url

* Fix space in Vulkan

* Remove dead link (user web directory no longer exists)

* Remove dead link (file deleted)

* Remove dead link (file deleted)

* Remove dead link (domain non-existent)

* Correct number or blank lines between sections

* Remove missing sections from contents

* Update free-courses-ko.md

* Update free-courses-ko.md

* Update Deep Learning

* delete (youtube) tag

* add resource Belajar Dengan Jenius Golang

* fix blank lines

* replace resource with raw link

* added Spring framework PDF

* Update free-programming-books.md

Fixed spelling

* add Deploy em produção para desenvolvedores

* add screencast go lang

* Update free-podcasts-screencasts-pt_BR.md
Co-authored-by: NSeth <seth@elypia.org>

* empty lines
Co-authored-by: NGeorge Rodrigues <georgeamaral@grendene.com.br>
Co-authored-by: NSeth <seth@elypia.org>

* Add My Free Java Course to free-courses-en list

* Removed empty spaces and added author

* Add python kaggle course to free-courses-en list

* Updated Java Course with direct link and correct name

* Removed extra white space around hyphen

* Add "A byte of Python"

* Move link up for correct order

* Update link to source

* Add german source again

* Create free-courses-fr.md

Create french free courses page

* Update free-courses-fr.md

* Update free-courses-fr.md

* Update free-programming-books-fr.md

* Delete free-courses-fr.md

* Update free-programming-books-fr.md

Adding additional note

* Move Clojure section to follow alphabetical order

* Fix heading level of Groovy related sections

* Update TOC to follow sections below

* Merge duplicated sections

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

* elixir Podcast

* fix
Co-authored-by: Nsarit <sarit.pinhas@duda.co>

* DS Podcast

* secure

* fix
Co-authored-by: Nsarit <sarit.pinhas@duda.co>

* Css Podcast

* fix
Co-authored-by: Nsarit <sarit.pinhas@duda.co>

Co-authored-by: Nsarit <sarit.pinhas@duda.co>

* add Deno book to free-programming-books-zh

* try to fix

Incorrect number of blank lines between last section and next heading  blank-lines

* add author of Deno进阶开发笔记

* update file

added best data science learning tutorial

* update file

* update file

adding most popular deep learning playlist

* update file

* update file

* update file

* Update free-courses-th.md

Add free Python course

* Update free-courses-th.md
Co-authored-by: NSeth <seth@elypia.org>
Co-authored-by: NSeth <seth@elypia.org>

* add link to cheatsheets

* fix ordering in courses-id

* Added git, CSS, HTML, and JS cheatsheets

* Update formatting and added to Table of Contents
Co-authored-by: Neric <eric@hellman.net>

* Update problem-sets-competitive-programming.md

Added Practice Python to Problem Sets

* Update problem-sets-competitive-programming.md

* Added 1 C book and 3 authors.

C
Added 1 new book and 3 missing authors in the list.

* Added a bunch of authors.

C++

* C#

Added an author.

* Added 2 HTML books and 1 format.

* Ordering Change.

* Another One.

* Adds Building Secure & Reliable Systems

* Adds (PDF) mark

* Moves (PDF) mark to after the author

* Added a podcast and an spanish resource

* fixed order and URL

Added R programming resource for program evaluation - Summary and Analysis of Extension Program Evaluation in R (#4794)

check_urls=free-programming-books.md