PCB Doc Update:  J5 MM Load

I was testing for short circuits after soldering on the power headers. It surprised me that one of them beeped.

Mention in step 3.2 or 3.4 that is normal when testing for continuity for power header J5 (MM Load) that it may briefly beep for less than a second.

Note: I have saved step 3.2 for last while I waited for the power headers to ship. All the capacitors were installed already.