gh-101100: Fix datetime reference warnings

[smontanaro]

Fixed dangling references. datetime, date, and time classes have many method names in common (not too surprising). Where it didn't seem to make a difference, I changed the reference to the datetime version of the method.

• Issue: Fix all Sphinx reference warnings in the documentation #101100

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📚 Documentation preview 📚: https://cpython-previews--114661.org.readthedocs.build/

[smontanaro]

@serhiy-storchaka I applied your suggestions, then got a bit carried away. It seems to me that if :attr:!tm_isdst is appropriate when several references are close together, then self-referential module references should be suppressed in most places. Accordingly, I replaced instances of

:mod:`datetime` 

with

:mod:`!datetime` 

to suppress the link to the documentation the user is currently viewing. If there's a good reason to retain these links, let me know and I'll undo that part of the change.

[smontanaro]

I've responded to all recent comments.

[serhiy-storchaka]

Many references `attr<datetime.attr>` can be shortened to `~.datetime.attr`. Or, if you prefer the long form, they should be written as `~datetime.datetime.attr` or `attr <datetime.datetime.attr>`. Currently they only work by accident and can be broken after adding new global in the datetime module.

[serhiy-storchaka]

LGTM. 😌

[smontanaro]

Thanks. Feel free to merge. (I don't have -- or want -- check-in privilege.)

[miss-islington-app]

Thanks @smontanaro for the PR, and @serhiy-storchaka for merging it 🌮🎉.. I'm working now to backport this PR to: 3.11, 3.12.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @smontanaro and @serhiy-storchaka, I could not cleanly backport this to 3.11 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker e8b8f5e9c2da6a436360ce648061c90bdfcba863 3.11 

[bedevere-app]

GH-114716 is a backport of this pull request to the 3.12 branch.

[serhiy-storchaka]

Thank you @smontanaro. It was a complicated issue.

The documentation can still be refined: there are paragraphs with repeated links. But this is a different issue.

[serhiy-storchaka]

Please look also at #114717.

[bedevere-app]

GH-114718 is a backport of this pull request to the 3.11 branch.