[DOC][RP2040]cmake command in readme

[kaidegit]

Describe the issue
In the readme of RP2040 port, here offered a command import(FreeRTOS_Kernel_import.cmake). However, my cmake raised an error Unknown CMake command "import".. I also seen the command to import freertos in pico-example using include rather than import. Is there a typo?

Reference
the readme

the example

[paulbartell]

@kaidegit This is indeed a typo. Thanks for the report.