Apply refurb suggestions

[DimitriPapadopoulos]

• [FURB107] Replace try: ... except ImportError: pass with with suppress(ImportError): ...
• [FURB109] Replace in [x, y, z] with in (x, y, z)
• [FURB113] Use x.extend(...) instead of repeatedly calling x.append()
• [FURB123] Replace list(x) with x.copy()

Not fixing all of them: some are debatable and other result in less readable (by me) code.

https://github.com/dosisod/refurb

TODO:

• [ ] Unit tests and/or doctests in docstrings
• [ ] tox -e py310 passes locally
• [ ] Docstrings and API docs for any new/modified user-facing classes and functions
• [x] Changes documented in docs/release.rst
• [ ] tox -e docs passes locally
• [x] GitHub Actions CI passes
• [x] Test coverage to 100% (Coveralls passes)