[`flake8-pyi`] Implement autofix and handle nested unions with single element (`PYI041` , `PYI055`) #35375

Job	Run time
pre-commit	1m 10s
Determine changes	11s
cargo fmt	22s
mkdocs	2m 42s
python package	1m 20s
benchmarks	4m 54s
cargo build (release)	4m 38s
cargo build (msrv)	3m 51s
cargo clippy	1m 59s
cargo fuzz	4m 48s
cargo shear	31s
cargo test (linux)	4m 5s
cargo test (wasm)	1m 38s
cargo test (windows)	8m 55s
formatter instabilities and black similarity	0s
test scripts	1m 0s
ecosystem	9m 10s
test ruff-lsp	33s
Fuzz the parser	0s
	51m 47s

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