Fixed ("C" to "C#")

Trailing hash signs (#) in headers are ignored. I fixed that with a HTML escape sequence.

free-podcasts-screencasts-en.md

@@ -28,7 +28,7 @@
 * [Podcast] - [Adventures in Angular - DevChat.tv](https://devchat.tv/adventures-in-angular/)
 
 
-### C#
+### C#
 
 * [Screencast] - [How to program in C# - Beginner Course | Brackeys](https://www.youtube.com/playlist?list=PLPV2KyIb3jR6ZkG8gZwJYSjnXxmfPAl51)