Rephrase bus speed cautions for clarity

Author: dhalbert

adafruit_mlx90614.py

@@ -75,8 +75,8 @@ class MLX90614:
     """Create an instance of the MLX90614 temperature sensor.
 
     :param ~busio.I2C i2c_bus: The I2C bus the MLX90614 is connected to.
-                               frequency=100000 - this sensor does not
-                               respond to a  400000 i2c bus speed
+                               Do not use an I2C bus speed of 400kHz. The sensor only works
+                               at the default bus speed of 100kHz.
     :param int address: I2C device address. Defaults to :const:`0x5A`.
 
     **Quickstart: Importing and using the MLX90614**

examples/mlx90614_simpletest.py

@@ -15,8 +15,8 @@
 import board
 import adafruit_mlx90614
 
-# the mlx90614 must be run at 100k [normal speed]
-# the mlx90614 will not appear at the 400k speed
+# The MLX90614 only works at the default I2C bus speed of 100kHz.
+# A higher speed, such as 400kHz, will not work.
 i2c = board.I2C()
 mlx = adafruit_mlx90614.MLX90614(i2c)