cipher: allow getting the proto of a ciphersuite #1623

Job	Run time
Clippy nightly (optional)	45s
Clang Tidy	7s
Clippy	42s
Build+test (clang, aws-lc-rs, stable, ubuntu-latest)	2m 27s
Check for documentation errors	31s
Build+test (clang, aws-lc-rs, beta, ubuntu-latest)	2m 34s
ensure-header-updated	1m 19s
Format	14s
Build+test (clang, aws-lc-rs, nightly, ubuntu-latest)	2m 28s
Build+test (clang, aws-lc-rs, 1.64.0, ubuntu-latest)	4m 31s
Check minimum versions	1m 20s
Miri	1m 4s
Build+test (clang, ring, stable, ubuntu-latest)	1m 32s
Windows CMake, Debug configuration (aws-lc-rs)	2m 27s
Build+test (clang, ring, beta, ubuntu-latest)	1m 27s
Windows CMake, Debug configuration (ring)	1m 47s
Windows CMake, Release configuration (aws-lc-rs)	3m 52s
Build+test (clang, ring, nightly, ubuntu-latest)	1m 29s
Valgrind	2m 35s
Windows CMake, Release configuration (ring)	3m 4s
Build+test (clang, ring, 1.64.0, ubuntu-latest)	3m 24s
Build+test (gcc, aws-lc-rs, stable, ubuntu-latest)	2m 5s
Build+test (gcc, aws-lc-rs, beta, ubuntu-latest)	2m 4s
Build+test (gcc, aws-lc-rs, nightly, ubuntu-latest)	2m 5s
Build+test (gcc, aws-lc-rs, 1.64.0, ubuntu-latest)	4m 14s
Build+test (gcc, ring, stable, ubuntu-latest)	1m 24s
Build+test (gcc, ring, beta, ubuntu-latest)	1m 19s
Build+test (gcc, ring, nightly, ubuntu-latest)	1m 25s
Build+test (gcc, ring, 1.64.0, ubuntu-latest)	3m 25s
Build+test (macos-latest, clang, aws-lc-rs, stable)	2m 51s
	1h 0m 31s

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