message: docs(api): Fix typo in mix command example
  Fixed typo in Mix command example
  Fixed a typo in the Mix command example code. Changed line 360 from     pipette.mix(4, 100, plate.['A2']) to     pipette.mix(4, 100, plate['A2']). Removed the period.
diff: @@ -357,7 +357,7 @@ The ``mix`` command takes up to three arguments: ``mix(repetitions, volume, loca
  .. code-block:: python
  # mix 4 times, 100uL, in plate:A2
  - pipette.mix(4, 100, plate.['A2'])
  + pipette.mix(4, 100, plate['A2'])
  # mix 3 times, 50uL, in current location
  pipette.mix(3, 50)
  # mix 2 times, pipette's max volume, in current location
  