Update free-courses-hi.md (#10547)

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Updated link of reference playlist

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I have reviewed the document and replaced any invented titles with the correct

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Removed all CAPS

courses/free-courses-hi.md

@@ -221,6 +221,7 @@
 
 * [Compiler Design](https://www.youtube.com/playlist?list=PL9FuOtXibFjVR-87LcU-DS-9TJcbG97_p) - Abhishek Sharma
 * [Compiler Design](https://www.youtube.com/playlist?list=PL23dd-8zssJBiyntds3X1sVWUDeb0Aa1N) - Start Practicing
+* [Compiler Design (Complete Playlist)](https://www.youtube.com/playlist?list=PLmXKhU9FNesSmu-_DKC7APRoFkaQvGurx) - KnowledgeGATE by Sanchit Sir
 * [Compiler Design (Complete Playlist)](https://www.youtube.com/playlist?list=PLxCzCOWd7aiEKtKSIHYusizkESC42diyc) - Gate Smashers
 * [Compiler Design Tutorial In Hindi](https://www.youtube.com/playlist?list=PL-JvKqQx2Ate5DWhppx-MUOtGNA4S3spT) - University Academy