add the "__prepare__" method to the list of recognized dunder method

[takaya0]

Summary

Closes #9508 .
Add __prepare__ method to dunder method list in is_known_dunder_method.

Test Plan

1. add "prepare" method to Apple class in crates/ruff_linter/resources/test/fixtures/pylint/bad_dunder_method_name.py.
2. run cargo test

[charliermarsh]

Thanks!

[codspeed-hq]

CodSpeed Performance Report

Merging #9529 will improve performances by 4.55%

_{Comparing takaya0:PLW3201-add-prepare-to-known-dunder-method (98a9db3) with main (66804ec)}

Summary

⚡ 1 improvements
✅ 29 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	takaya0:PLW3201-add-prepare-to-known-dunder-method	Change
⚡	parser[numpy/ctypeslib.py]	12.8 ms	12.2 ms	+4.55%

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.