Fix comments cable mapping (and PEP8)
Created by: jorana
What is the problem / what does the code in this PR do
- Add more info about remapping channels and provide reference. See https://github.com/XENONnT/straxen/pull/166 and https://xe1t-wiki.lngs.infn.it/doku.php?id=xenon:xenonnt:dsg:daq:sector_swap for reference. @tunnell pointed out that the description in the context is minimal. This PR adds some more info (in addition to the readily available info already in context.py).
- There were also some PEP8 and indentation issues with the context that are fixed on the fly.