Comments and docstring changes only
> - https://github.com/bitcoin/bitcoin/pull/17578#discussion_r363969721
> - https://github.com/bitcoin/bitcoin/pull/17578#discussion_r362703553
This is a backport of Core PR17585 [1/5]
https://github.com/bitcoin/bitcoin/pull/17585/commits/c7654af6f830577a54df12b5d65df93532db0dc2