Add `to_angle` method to 2D vectors #1042

Job	Run time
Lint	3m 19s
Test portable simd (ubuntu-latest, nightly)	1m 21s
Test wasm (stable, ubuntu-latest)	6m 27s
Test portable simd (macos-latest, nightly)	2m 5s
Test portable simd (windows-latest, nightly)	1m 54s
Test (ubuntu-latest, stable)	3m 28s
Test (ubuntu-latest, beta)	3m 17s
Test (ubuntu-latest, nightly)	3m 33s
Test (macos-latest, stable)	3m 50s
Test (macos-latest, beta)	6m 29s
Test (macos-latest, nightly)	5m 38s
Test (windows-latest, stable)	5m 37s
Test (windows-latest, beta)	5m 39s
Test (windows-latest, nightly)	5m 28s
	58m 5s

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