Correcting the docs on two MIDI properties for channels based on @tannewt feedback from adafruit#9. adafruit#3.

Author: Kevin J Walters

adafruit_midi/__init__.py

@@ -91,9 +91,9 @@ def __init__(self, midi_in=usb_midi.ports[0], midi_out=usb_midi.ports[1], *,
     @property
     def in_channel(self):
         """The incoming MIDI channel. Must be 0-15. Correlates to MIDI channels 1-16, e.g.
-        ``in_channel(3)`` will listen on MIDI channel 4.
-        Can also listen on multiple channels, e.g. ``in_channel((0,1,2))``
-        will listen on MIDI channels 1-3 or ``in_channel("ALL")`` for every channel.
+        ``in_channel = 3`` will listen on MIDI channel 4.
+        Can also listen on multiple channels, e.g. ``in_channel  = (0,1,2)``
+        will listen on MIDI channels 1-3 or ``in_channel = "ALL"`` for every channel.
         Default is None."""
         return self._in_channel
 
@@ -112,7 +112,7 @@ def in_channel(self, channel):
     @property
     def out_channel(self):
         """The outgoing MIDI channel. Must be 0-15. Correlates to MIDI channels 1-16, e.g.
-        ``out_channel(3)`` will send to MIDI channel 4. Default is 0."""
+        ``out_channel = 3`` will send to MIDI channel 4. Default is 0 (MIDI channel 1)."""
         return self._out_channel
 
     # pylint: disable=attribute-defined-outside-init