Docs: InferenceShifter,ModelResult,SensorInput,InferenceType

[rhyolight]

fixes #3548

[rhyolight]

@scottpurdy can you help here (or suggest someone to help)?

[scottpurdy]

It looks like this class is just an abstraction over the encoders. The category comes from categoryOut on the sensor region:

https://github.com/numenta/nupic/blob/914ada4fa719609e1523ca5c54c6e06b5b223bd3/src/nupic/frameworks/opf/htmpredictionmodel.py#L448

And in that code you can also see how dataRow comes from the sensor sourceOut while dataDict is the input to the sensor. Interestingly, these are both the unencoded values so I think they are just different forms of the same thing?

And the intent of this class isn't fully clear to me so hard to know the right thing to put in the documentation.

[rhyolight]

@scottpurdy I'm happy with this if you are