doc: revisions to config.py and parameter display

This PR changes the way some of the parameters are described, and I would like agreement on these, hence the PR.

e.g. old line 34, new 40. I found "(0, 1)' quite a confusing way to present parameters and is also slightly inconsistent as it's normally a type description....

I battled to resolve this issue to my satisfaction here due to the "all settings are actually strings" thing in the configparser backend. Have the same settings described for ini files and the Python types was tricky. e.g. old line 99, new line 106? Hmm...