Add submission # 5503

#5503

Author: ArduinoBot

registry.txt

@@ -7648,3 +7648,4 @@ https://github.com/EmotiBit/EmotiBit_KTD2026.git|Contributed|EmotiBit KTD2026
 https://github.com/SimonVonSchmude/Cabluino.git|Contributed|Cabluino
 https://github.com/kkeonline/LineMessagingAPI.git|Contributed|LineMessgingAPI
 https://github.com/UnexpectedMaker/RGB-Touch-Mini-Arduino-Helper.git|Contributed|UM RGB Touch Mini
+https://github.com/ktauchathuranga/telnet.git|Contributed|Telnet