Tests

Add .choices() method to the Slice distribution #704

Job	Run time
test-ios	25s
test-cross (ubuntu-latest, powerpc-unknown-linux-gnu, stable)	1m 27s
Check doc	1m 7s
test (ubuntu-latest, x86_64-unknown-linux-gnu, stable)	1m 0s
test-miri	2m 18s
test (macos-latest, x86_64-apple-darwin, stable)	2m 17s
test-no-std	14s
test (windows-latest, x86_64-pc-windows-gnu, stable)	2m 41s
test (windows-latest, x86_64-pc-windows-msvc, beta)	1m 42s
test (ubuntu-latest, x86_64-unknown-linux-gnu, MSRV, 1.60.0)	4m 34s
test (ubuntu-latest, sudo apt-get update ; sudo apt install gcc-multilib, i686-unknown-linux-gnu,...	2m 11s
test (ubuntu-latest, x86_64-unknown-linux-gnu, nightly, minimal_versions)	34s
	20m 30s

Provide feedback