add catalan data structures book

[Pablito2020]

What does this PR do?

Add resource(s)

For resources

Description

This pull request adds a book about datastructures and algorithms created by some professors of the University of Lleida.

Why is this valuable (or not)?

Could be valuable for people trying to understand some data structures like graphs, linkedlists, etc and they want a book about this topic that is written in catalan.

How do we know it's really free?

It is licensed behind a Creative Commons license, which has:
Attribution, Non commercial and no derivatives.

For book lists, is it a book? For course lists, is it a course? etc.

This is a book (has an ISBN: 978-84-9144-101-4)

Checklist:

• Read our contributing guidelines.
• Search for duplicates.
• Include author(s) and platform where appropriate.
• Put lists in alphabetical order, correct spacing.
• Add needed indications (PDF, access notes, under construction).
• Used an informative name for this pull request.

[Pablito2020]

I am participating on HacktoberFest, so I would like to have the "Hacktoberfest-accepted" label if it is possible 😄 .

[eshellman]

language code is ca.
You want TWO index headings for one resource?
It's usually not helpful to add a category for a single resource. Try to find another category, or see if there are other books in our lists that would fit into your category.

[Pablito2020]

Hi @eshellman! The commit 5d51b3d fixes the issues you commented in the pull request review 😃 .

The two books I've added one is a book-wiki about C, and the other is licensed with a creative commons with non commercial derivatives.

Cheers!

[Pablito2020]

Some maintainer will review again this pull request? 7 days have passed and the project is accepting other pull requests. Should I change something more?

[eshellman]

you have not fixed the language code. it should be ca, not es_CA

[eshellman]

see #9109