[Wiki Update] Demand on RP2040 pin_arduino.h usage for SenseCAP Indicator

[Love4yzp]

Actually, I think there lacks a knowleage of using the pin_arduino.h in Arduino IDE.
As you could see, you can change the pin numbers to have a hardware Serial setup for RP2040. Seeed-Solution/SenseCAP_Indicator_ESP32#49

And there is no reference to tell the usage.