Allow in-place option in configuration files

[janosh]

Setting

# setup.cfg
[docformatter]
in-place = true

has no effect.

docformatter --config setup.cfg path/fo/file.py

still prints to terminal, leaving path/fo/file.py unchanged.

[weibullguy]

@janosh there are some options that can't be configured in the config files. These are --in-place, --check, --diff, and --exclude. These must be passed with the command. This isn't documented as it should be, so it's understandable you reported this as a bug. I am updating the title of this issue to reflect your report as a request for a new feature to be included in v1.6.0.