ci: Remove llvm 5, introduce llvm 16 #1847

Job	Run time
minimal	37s
msrv	2m 44s
docs	24s
rustfmt-clippy	37s
check-cfg	20s
quickchecking	19s
test (ubuntu-latest, 9.0, 1, 0, 0, 0, 0)	28s
test-expectations (ubuntu-latest)	53s
test (ubuntu-latest, 9.0, 1, 0, 0, 1, 0)	16s
test-book	15s
test-expectations (macos-latest)	2m 32s
test (ubuntu-latest, 9.0, 1, 0, 1, 0, 0)	28s
test (ubuntu-latest, 9.0, 1, 0, 1, 1, 0)	22s
test (ubuntu-latest, 9.0, 1, 1, 0, 0, 0)	31s
test (ubuntu-latest, 9.0, 1, 1, 0, 1, 0)	29s
test (ubuntu-latest, 9.0, 1, 1, 1, 0, 0)	30s
test (ubuntu-latest, 9.0, 1, 1, 1, 1, 0)	30s
test (ubuntu-latest, 16.0, 1, 0, 0, 0, 0)	31s
test (ubuntu-latest, 16.0, 1, 0, 0, 1, 0)	32s
test (ubuntu-latest, 16.0, 1, 0, 1, 0, 0)	29s
test (ubuntu-latest, 16.0, 1, 0, 1, 1, 0)	28s
test (ubuntu-latest, 16.0, 1, 1, 0, 0, 0)	29s
test (ubuntu-latest, 16.0, 1, 1, 0, 1, 0)	29s
test (ubuntu-latest, 16.0, 1, 1, 1, 0, 0)	18s
test (ubuntu-latest, 16.0, 1, 1, 1, 1, 0)	28s
test (ubuntu-latest, 16.0, 0, 0, 1)	30s
test (macos-latest, 16.0, 0, 0, 0)	11s
	16m 40s

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