Implement `Neg` for `Direction2d` and `Direction3d` #34099

Job	Run time
build (windows-latest)	4m 54s
check-doc	5m 42s
check-missing-examples-in-docs	28s
build (ubuntu-latest)	2m 30s
ci	2m 5s
miri	6m 56s
run-examples-on-windows-dx12	13m 16s
build (macos-latest)	5m 45s
toml	5s
check-bevy-internal-imports	4s
check-missing-features-in-docs	29s
markdownlint	1m 17s
check-compiles	2m 53s
build-wasm	58s
msrv	59s
	48m 21s

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