message: Fix comment on env var
diff: @@ -8,8 +8,10 @@ RECOVERY_TIMEOUT = 10
  DEFAULT_SERIAL_TIMEOUT = 5
  DEFAULT_WRITE_TIMEOUT = 30
  -# Note: FT232R is the board id for communication over usb on UNIX systems.
  -# This is set for serial communication in the Dockerfile
  +# Note: FT232R is the chip id for the serial-to-UART cables used to connect to
  +# the robot. This value will usually be correct, if using a usb-to-UART cable
  +# with this chip. Otherwise, set the env var to whatever identifier is used for
  +# the serial connection.
  smoothie_id = os.environ.get('OT_SMOOTHIE_ID', 'FT232R')
  ERROR_KEYWORD = b'error'
  