Add `half::f16` and `half::bf16` support #556

Job	Run time
clippy/stable	19s
format/nightly	17s
miri	9m 49s
Pass MSRV values to other jobs	2s
cargo-careful	2m 6s
nostd/thumbv6m-none-eabi/stable	16s
cross_test/i686-unknown-linux-gnu/stable	2m 35s
cross_test/s390x-unknown-linux-gnu/stable	9m 53s
docs/nightly	24s
blas-msrv	1m 27s
tests/stable	2m 49s
tests/beta	2m 42s
tests/nightly	3m 9s
tests/1.64.0	6m 2s
conclusion	-1s
	41m 49s

Provide feedback