added sinhala courses (#5934)

* added sinhala courses

* updateted free-courses-sl.md

* free-courses-sl.md updated v2

* Update courses/free-courses-sl.md

Update courses/free-courses-sl.md v3
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-sl.md

Update courses/free-courses-sl.md v4
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-sl.md v5

Update courses/free-courses-sl.md v5
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-sl.md

Update courses/free-courses-sl.md v6
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-sl.md

Update courses/free-courses-sl.md v6
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-sl.md

Update courses/free-courses-sl.md v7
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-sl.md

Update courses/free-courses-sl.md v8

* updated free-courses-sl.md 

resolved empty catogory
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README.md

@@ -94,6 +94,7 @@ 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)
 + [Spanish / español / castellano](courses/free-courses-es.md)
 + [Thai / ภาษาไทย](courses/free-courses-th.md)
 + [Turkish / Türkçe](courses/free-courses-tr.md)

courses/free-courses-sl.md

+### Index
+
+* [ASP.NET Core](#aspnet_core)
+* [HTML / CSS](#html--css)
+* [Java](#java)
+* [JavaScript](#javascript)
+  * [React](#react)
+
+
+### ASP.NET Core
+
+* [WEB API-ASP.NET Core in Sinhala](https://youtube.com/playlist?list=PLvvtf05eMZ2CpeAsq93DqWJHHyvCSa2Qn) - Fiqri Ismail (YouTube)
+
+
+### HTML / CSS
+
+* [HTML සිංහලෙන්](https://youtube.com/playlist?list=PLWAgeLqk4SjDlN6nHs91rECgx4PbzfoZh) - SL Geek School (YouTube)
+
+
+### Java
+
+* [Sinhala Java Netbeans Lessons](https://youtube.com/playlist?list=PLA3ZeQncjeVu9VHevp2SmPCQ9muVO3fEB) - Chanux Bro (YouTube)
+
+
+### JavaScript
+
+* [JavaScript Tutorial in Sinhala](https://youtube.com/playlist?list=PLYmyc7wRFoQjxkHAzHh1UIdU7ZdjTQvQt) -BestJobsLK (YouTube)
+
+
+#### React
+
+* [Fundamentals \| React JS in Sinhala](https://youtube.com/playlist?list=PLvvtf05eMZ2DpDyWwmAjEuicvVxx4vIYB) - Fiqri Ismail (YouTube)
+