Add comment for quick switching between alternative libaries.

Author: David R Forrest

examples/PID_simulated_heater_disp/PID_simulated_heater_disp.ino

@@ -11,6 +11,7 @@
 //  Wokwi https://wokwi.com/projects/357374218559137793
 //  Wokwi https://wokwi.com/projects/356437164264235009
 
+//#include "PID_v1.h" // https://github.com/br3ttb/Arduino-PID-Library
 #include "PID_v1_bc.h" // https://github.com/drf5n/Arduino-PID-Library
 
 //Define Variables we'll be connecting to