Added Compilers Design Course (#7491)

* Added Compilers Design Course

* fix: use YT playlist urls

* lint: alphabetize

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

courses/free-courses-en.md

@@ -276,6 +276,7 @@
 
 ### Compilers
 
+* [Compiler Design](https://www.youtube.com/playlist?list=PLLvKknWU7N4zpJWLqk7DXK26JwTB-gFmZ) - Lalit Vashistha
 * [Compiler Design](https://youtube.com/playlist?list=PLBlnK6fEyqRjT3oJxFXRgjPNzeS-LFY-q) - Neso Academy
 * [Compilers](https://www.youtube.com/playlist?list=PL6KMWPQP_DM97Hh0PYNgJord-sANFTI3i) - Ghassan Shobaki (YouTube)
 * [Stanford's Compilers](https://www.edx.org/course/compilers)