Disable more Pylint messages
Disable `no-else-returns` for structures like
if condition:
return 1
else:
return 2
In some cases using `else` here is more "symmetrical" and thus reads
better.
Disable `unnecessary-pass`. This applies mostly to custom exception
classes that have both a docstring and a `pass` after that. I think
the `pass` looks good here, even if Python doesn't require it.
Of course I could disable these messages only for the above cases,
but I think it's not justified to clutter the code with the pragmas
if "violating" the respective rule is harmless.
