gh-120784: Reword utcnow/utcfromtimestamp deprecation warning to use datetime.timezone.utc

[nineteendo]

It's better to point to datetime.timezone.utc as datetime.UTC was only added in Python 3.11.
No need to suggest to make code backwards incompatible without a good reason.

• Issue: UTC deprecation doc-string is false #120784

[pganssle]

I think I am -0 on this change. I chose the datetime.UTC wording deliberately because it advertises that the datetime.UTC singleton exists, which allows people to do things like from datetime import UTC; datetime.now(UTC) (which is the same number of characters as datetime.utcnow(), which some people care about).

I would not think that we should be so concerned with backwards compatibility, since this deprecation warning only even happens in Python 3.12+, and it's referring to a removal that won't take place for an indefinite amount of time in the future.

Evidently some people are indeed confused by this, though, so I dunno, maybe it's better on net to recommend the wordy version? 🤷

[pganssle]

As I mentioned, I'm not really in favor of merging this, but if we do end up merging it, it should probably get a news blurb.

[bedevere-app]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[nineteendo]

Ruff also mentions datetime.timezone.utc first:

• https://docs.astral.sh/ruff/rules/call-datetime-utcnow
• https://docs.astral.sh/ruff/rules/call-datetime-utcfromtimestamp

Would you prefer to mention both too?

[nineteendo]

pganssle, I have made the requested changes; please review again.

[bedevere-app]

Thanks for making the requested changes!

@pganssle: please review the changes made to this pull request.

[merwok]

I agree with Paul, the warning is not wrong and this is not really a bug.