Slovenian language introduced (#6176)

* Slovenian language introduced

* Additional changes on Slovenian language

Author: BlazOrazem

Diff for: HOWTO-sl.md

@@ -0,0 +1,17 @@
+Preberite to v drugih jezikih: [Français](HOWTO-fr.md), [Español](HOWTO-es.md), [简体中文](HOWTO-zh.md), [हिन्दी](HOWTO-hi.md), [繁體中文](HOWTO-zh_TW.md), [Português (BR)](HOWTO-pt_BR.md), [فارسی](HOWTO-fa_IR.md), [Русский](HOWTO-ru.md), [Deutsch](HOWTO-de.md), [Bahasa Indonesia](HOWTO-id.md), [Tiếng Việt](HOWTO-vi.md), [عربي](HOWTO-ar.md).
+
+Dobrodošli v zbirki Free-Programming-Books! Lepo pozdravljeni vsi novi programerji - tudi tisti, ki boste na Githubu ustvarili vaš prvi zahtevek potega (pull-request). Če ste eden izmed njih, vam pri tem lahko pomaga nekaj virov:
+
+* [About Pull Requests](https://help.github.com/articles/about-pull-requests/)
+* [Creating a pull request](https://docs.github.com/en/free-pro-team@latest/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request)
+* [Github Hello World](https://guides.github.com/activities/hello-world/)
+* [Youtube - Github Tutorial For Beginners](https://www.youtube.com/watch?v=0fKg7e37bQE)
+* [Youtube - How To Fork A GitHub Repo and Submit A Pull Request](https://www.youtube.com/watch?v=G1I3HF4YWEw)
+* [Youtube - Markdown Crash Course](https://www.youtube.com/watch?v=HUBNt18RFbo)
+
+
+Ne oklevajte in postavljajte vprašanja; vsak programer je enkrat začel s svojim prvim PR-om. Vi ste lahko naš tisoči!
+
+Tudi če ste izkušeni na področju programiranja odprte kode, se bodo zagotovo našle zadeve, ki vas lahko malce zaustavijo. Ko oddate PR, bo GitHub Actions zagnal pregledovalnik, ki pogosto najde manjše težave z razmikom ali abecedo. Če se vam prikaže zeleni gumb, je vse pripravljeno za pregled. Če se zeleni gumb ne prikaže, kliknite »Podrobnosti« pod kljukico, ki je ugotovila, kaj pregledovalniku ni bilo všeč. Odpravite težavo in dodajte zahtevo (commit) v PR.
+
+Če niste prepričani, da je vir, ki ga želite dodati, primeren za zbirko Free-Programming-Books, preberite smernice v [CONTRIBUTING](CONTRIBUTING.md).

Diff for: README.md

@@ -95,7 +95,7 @@ Please read [CONTRIBUTING](CONTRIBUTING.md). If you're new to GitHub, [welcome](
 + [Portuguese (Brazil)](courses/free-courses-pt_BR.md)
 + [Portuguese (Portugal)](courses/free-courses-pt_PT.md)
 + [Russian / Русский язык](courses/free-courses-ru.md)
-+ [Sinhala / සිංහල](courses/free-courses-sl.md)
++ [Sinhala / සිංහල](courses/free-courses-si.md)
 + [Spanish / español / castellano](courses/free-courses-es.md)
 + [Thai / ภาษาไทย](courses/free-courses-th.md)
 + [Turkish / Türkçe](courses/free-courses-tr.md)