M950 should mention than S and P numbers are shared

[kuon]

I am not sure if this is a bug or if this is expected, but I have an M950 S0 for my bltouch, and I tried to add M950 P0 for an IO output (water pump relay), and I had very weird behavior. I renumbered M950 P1 and the issue was gone.

My conclusion is that Px and Sx parameters share "slots" and should not have the same number and this should be mentioned in the doc.

[droftarts]

@kuon Sorry for the slow reply. I added the following to the M950 description a while ago:

Pnn or Snn Output/servo pin number. Each P and/or S number needs to be unique, eg P1, P2, S3 P4, S5 etc. Servo pins are GpOut pins with a different default PWM frequency.

Ian