CLN apply pep257 via docformatter
Not really for merging, but I wanted to see how [docformatter](https://github.com/myint/docformatter) handled codebase (e.g. any bugs). Perhaps we can make these changes incrementally.

cc #6248

I skimmed though the first third and last third line changes... haven't checked the middle section (as there are many)

cc @myint Are the last couple of comments bugs ? Also, the second (and third) commit here is from a second (resp. third) pass of docformatter... so potentially these changes are not correct? After third pass it stabilises.
 The sentence splitting is based on heuristic regular expression. It certainly can be faulty.

The underline removal was intended as I purposely used docformatter in the past to get rid of them. That feature probably should removed though.

The indenting seems odd. docformatter is supposed to completely leave the description untouched if it looks at all complicated (has numbered list or has anything that cannot be simply wrapped).
 @myint thanks, hmm the regex is tricky, looks like it was just caught by an unlucky word wrap... in fact was manually word wrapped, so I think it's ok to be tripped up by that! Do you want me to post indenting as a sep issue?
 Sure.

Thanks
 @myint that is actually fixed in master (presumably as a weird case of the underline). :)
 There is a docformatter option of pep8radius. Anyway, I'm closing this, as too disruptive, maybe can do after pep8 splurge post 0.14.1.
