The "official" Dive Into Python links no longer go to the books. There is no great authoritative link to use since Mark Pilgrim left the internet, but these are returned high in Google results and appear to load really quickly.

* feat: Add "How to collaborate on Github"

* fix: wrong alpha order

current ng-newsletter link results in a 500 page. found an alternate link, but I suspect it is temporary until the newsletter fixes their 500, so we may not want to update the link. either way, this PR addresses #3400

* Remove dead link from free-programming-books-tr.md

* Change Django heading to same size as other headings

* Update link for Learning Deep Architectures

* revert django heading

* undo space add

* Adding OpenMP 5.0

* Adding PDF indicator

✔ Updated link of A Scala tutorial for Java programmers

✔ Updated link of Scala by Example

* Changed to new I Love Ruby website

* satisfy linter

* Added the React.js Succinctly.

* Update free-programming-books.md

* Included the Flutter, Azure Functions and Elixir Succinctly.

* Added two more books under flutter.

* Add Book Professional Development GitLab Handbook

* moved to Open Source Ecosystem and fixed warning

* Update free-programming-books.md

Add gidti eBook

* Add author name

* Add Mathematics Seven Sketches in Compositionalit

* Update free-programming-books.md

* Add Cloud Design Patterns

* fixed blanks

* Making games with TypeScript

* Remove trailing slash

link to more up to date version with better font

old: http://www.ethoberon.ethz.ch/WirthPubl/AD.pdf
new: https://inf.ethz.ch/personal/wirth/AD.pdf

previous docs were from 2005, found more recent docs from 2018

* Add a free JS resource on the list of free JS books.

* Alphabetical orderFix

"let's" > "leaflet"

* orderFix with eyes wide open.

T > A.

there were only links to v1.x django docs, so I added a link to the django 2.2 pdf docs

url = https://buildmedia.readthedocs.org/media/pdf/django/2.2.x/django.pdf

* added C Programming Language book PDF source

with reference to issues [3189](https://github.com/EbookFoundation/free-programming-books/issues/3189)
Added C Programming current standard PDF source.

* Add PDF indication

* Update deprecated links to Google's Android courses

* Renaming link to codelab in alphabetical order

* Rearrange in alphabetical order

* Remove Android Developer Fundamentals from books

* Add Android Developer Fundamentals to courses list

* Adding Harvard GSE Scratch Book

* adding raspberry pi press book

* spelling sorting doesn't ignore "an" as first word of title

* add introduction to Ada course book

* Change book to add

Add Ada for the C++ or Java Developer book instead.

* add author name to an ada book

* Update free-programming-books.md

* Update free-programming-books.md

* Update free-programming-books.md

Sorry for the error, fixed the spaces so that the linting will now work.

* Learn Azure in a Month of Lunches Book Added

* Learn Azure in a Month of Lunches Book Added

* Author Added

* IPv6 for IPv4 Experts english has been added

* IPv6 for IPv4 Experts russian has been added

* IPv6 for IPv4 Experts russian URL change

* IPv6 for IPv4 Experts english URL change