Support .pio assembly files

[maxgerhardt]

.pio files store assembly programs for the RP2040's programmable I/O state machine, e.g. per this example.

WizIO's platform has support for these files by converting them to .h files per the pioasm tool, as documented and programmed here.

[zapta]

Please include also support for editing the .pio file type. For example, Ctrl-/ for ';' comments, etc. Text coloring, etc.