Use type hinting generics in standard collections

[AndrewFerr]

aka PEP 585, added in Python 3.9

Dev notes

• https://peps.python.org/pep-0585/
• https://docs.astral.sh/ruff/rules/non-pep585-annotation/

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file. The entry should:
  • Be a short description of your change which makes sense to users. "Fixed a bug that prevented receiving messages from other servers." instead of "Moved X method from EventStore to EventWorkerStore.".
  • Use markdown where necessary, mostly for code blocks.
  • End with either a period (.) or an exclamation mark (!).
  • Start with a capital letter.
  • Feel free to credit yourself, by adding a sentence "Contributed by @github_username." or "Contributed by [Your Name]." to the end of the entry.
• Code style is correct (run the linters)

[MadLittleMods]

It's very hard to review this thoroughly as I don't want to click through 539 files on this diff. From a random sampling, I'm going to consider this good enough ✅

Due to the large number of changes in this pull request, only one file is being shown at a time.

[AndrewFerr]

What should alleviate that concern somewhat is the auto-fix rule for this PIP being enabled (b6f7a91), and lint/format/type checkers being satisfied with it.

The only handmade changes in this PR are:

• the two new # type: ignore comments
• the removal of unused imports from __init__.py files (as doing so is an in-preview feature of the unused-import Ruff rule)
• updates to docstrings, warnings, and comments (including # type: <type> comments) that referred to typing.* classes
• updates to the type strings for TestFieldTypeInspection in scripts-dev/check_pydantic_models.py

[MadLittleMods]

Here is what I also did:

1. git checkout develop
2. Start my own branch: git checkout -b madlittlemods/19046-see-diff
3. Edit pyproject.toml with the new ruff rules
4. Comment out ruff check --quiet --fix "${files[@]}" in scripts-dev/lint.sh so we can get to the auto-formatting part without it complaining
5. Lint and auto-format: poetry run ./scripts-dev/lint.sh
6. git commit -m "Auto-formatting changes"
7. git fetch origin refs/pull/19046/head:pr-19046
8. git diff madlittlemods/19046-see-diff pr-19046
9. (I looked through the actual diff here, looks sane ✅)

Summary:

$ git diff madlittlemods/19046-see-diff pr-19046 --numstat | xclip -selection clipboard
2	2	build_rust.py
1	0	changelog.d/19046.misc
54	58	pyproject.toml # This is just auto-formatting from my own `pyproject.toml` editing  in VSCode
7	7	scripts-dev/check_pydantic_models.py
1	1	synapse/__init__.py
1	1	synapse/_scripts/synapse_port_db.py
1	1	synapse/api/auth/__init__.py
0	2	synapse/appservice/__init__.py
3	1	synapse/config/saml2.py
0	4	synapse/events/__init__.py
0	3	synapse/federation/sender/__init__.py
1	1	synapse/federation/transport/server/__init__.py
1	1	synapse/federation/transport/server/_base.py
8	8	synapse/handlers/auth.py
3	1	synapse/handlers/oidc.py
1	1	synapse/handlers/sliding_sync/__init__.py
1	1	synapse/logging/context.py
0	4	synapse/metrics/__init__.py
0	3	synapse/module_api/__init__.py
1	1	synapse/notifier.py
1	1	synapse/push/__init__.py
1	1	synapse/rest/__init__.py
1	1	synapse/rest/admin/__init__.py
2	2	synapse/rest/admin/users.py
0	6	synapse/state/__init__.py
1	1	synapse/state/v2.py
1	1	synapse/storage/databases/__init__.py
1	1	synapse/storage/databases/main/__init__.py
1	1	synapse/storage/databases/main/events_bg_updates.py
1	1	synapse/storage/databases/main/registration.py
1	1	synapse/streams/__init__.py
0	5	synapse/types/__init__.py
1	1	synapse/types/handlers/__init__.py
1	1	synapse/types/rest/client/__init__.py
0	2	synapse/util/__init__.py
1	1	synapse/util/caches/__init__.py
0	1	tests/http/__init__.py
1	1	tests/push/test_email.py
1	1	tests/test_utils/__init__.py

[MadLittleMods]

Thanks for moving the codebase forward @AndrewFerr 🐠