Inspect `pcState` json doesn't have a comma if it's after another state

[MaartenS11]

For example, the message 0900020a01 will cause eventsState and pcState to be returned, but pcState doesn't check addComma like the other states, probably because of an incorrect assumption that it will always be first in the list of states.

Documentation:

... followed immediately by the IDs of those components in no particular order.

Example:

> 0900020a01
received interrupt 9
Interrupt: 9
DUMP!
{"events": []"pc":166}

Should be very simple to fix, but I thought I would just make an issue so we don't accidentally forget about it.