Improve PR review checklist

[ezio-melotti]

In python/cpython#93823 (comment) @erlend-aasland wrote a checklist about reviewing PRs.

In #914 (comment), I suggested:

SGTM -- that's a nice list. I think it would be easier to add it in a separate PR though.
Reviewing PRs is currently documented in two places:

• https://devguide.python.org/getting-started/pull-request-lifecycle/#reviewing
• https://devguide.python.org/triage/triaging/#reviewing-patches

The former has been likely written from scratch after the HG->Git migration, whereas the latter formerly documented how to review patches attached to a bpo issue and then it has been adapted to GitHub. I think the best approach would be to enhance the pull-request-lifecycle with your list, and remove the duplicated info in triaging.

[erlend-aasland]

Thanks for the PR! Can we close this?

[ezio-melotti]

#914 only included the changes that I had initially created, and I now merged it to keep things moving incrementally like Diataxis suggests.
The checklist you suggested in the comment linked above is more comprehensive and can still be integrated in the devguide to improve the current checklist, so I opened this issue as a reminder.

[abdnafees]

@ezio-melotti Can I please work on this issue?