Incorrect footprint library Nickname by default

[mekatrol]

When you import the footprint it defaults to the library name to MCU_RaspberryPi_and_Boards (as shown in example), however the symbol references the library nickname RPi_Pico. Access the footprint says the footprint file is not found as footprint name is RPi_Pico:RPi_Pico_SMD_TH.

Probably worth adding instruction to name the footprint library nickname to RPi_Pico instead of MCU_RaspberryPi_and_Boards.

This issue occurred in both KiCad 5 & 6.