ci: Remove llvm 5, introduce llvm 16 #1844

Job	Run time
rustfmt-clippy	31s
minimal	34s
msrv	2m 52s
check-cfg	23s
docs	23s
quickchecking	15s
test (ubuntu-latest, 9.0, 1, 0, 0, 0, 0)	13s
test-book	5s
test (ubuntu-latest, 9.0, 1, 0, 0, 1, 0)	13s
test (ubuntu-latest, 9.0, 1, 0, 1, 0, 0)	10s
test-expectations (ubuntu-latest)	18s
test (ubuntu-latest, 9.0, 1, 0, 1, 1, 0)	14s
test-expectations (macos-latest)	28s
test (ubuntu-latest, 9.0, 1, 1, 0, 0, 0)	20s
test (ubuntu-latest, 9.0, 1, 1, 0, 1, 0)	22s
test (ubuntu-latest, 9.0, 1, 1, 1, 0, 0)	22s
test (ubuntu-latest, 9.0, 1, 1, 1, 1, 0)	11s
test (ubuntu-latest, 16.0, 1, 0, 0, 0, 0)	14s
test (ubuntu-latest, 16.0, 1, 0, 0, 1, 0)	23s
test (ubuntu-latest, 16.0, 1, 0, 1, 0, 0)	14s
test (ubuntu-latest, 16.0, 1, 0, 1, 1, 0)	15s
test (ubuntu-latest, 16.0, 1, 1, 0, 0, 0)	12s
test (ubuntu-latest, 16.0, 1, 1, 0, 1, 0)	16s
test (ubuntu-latest, 16.0, 1, 1, 1, 0, 0)	14s
test (ubuntu-latest, 16.0, 1, 1, 1, 1, 0)	12s
test (ubuntu-latest, 16.0, 0, 0, 1)	14s
test (macos-latest, 16.0, 0, 0, 0)	7s
	10m 15s

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