[3.10] bpo-43882 - Mention urllib.parse changes in Whats new section.

[orsenthil]

https://bugs.python.org/issue43882

[gpshead]

I applied some formatting fixes to the rst. It'd be good to pull and update and do a manual docs build to make sure it formats okay.

[orsenthil]

I applied some formatting fixes to the rst. It'd be good to pull and update and do a manual docs build to make sure it formats okay.

I had copied the last merge from 3.7, and 3.6 for these to be consistent.

[orsenthil]

I will try building, and if I get any errors will update it. Not sure why the github diff is showing red.

[orsenthil]

Oh, btw, perhaps, I must have copied from the rendered docs. I will copy from the rst.

[orsenthil]

@gpshead - Thank you. :) This renders well and hyperlinks to RFC and modules are good.

[orsenthil]

The text was reviewed in #26268 these PR's port the text (with some format changes) to other active branches. Merging this.