message: docs(hardware): show how to use can_comm on mac
diff: @@ -39,6 +39,8 @@ opentrons_can_comm [-h] --interface INTERFACE [--bitrate BITRATE]
  [--channel CHANNEL] [--port PORT] [--host HOST]
  ```
  -Example using socketcan: `opentrons_can_comm --interface socketcan --channel vcan0`
  +On Linux using socketcan: `opentrons_can_comm --interface socketcan --channel vcan0`
  +
  +On Mac using pcan: `opentrons_can_comm --interface pcan --channel PCAN_USBBUS1 --bitrate 250000`
  Example using opentrons' CAN over socket: `opentrons_can_comm --interface opentrons_sock`
  