Improve map keys comparator

[MarshalX]

a little bit faster?

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #24 will degrade performances by 22.75%

_{Comparing improve-map-key-cmp (4c01a80) with main (6af9137)}

Summary

⚡ 1 improvements ❌ 7 (👁 7) regressions ✅ 184 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	improve-map-key-cmp	Change
👁	test_dag_cbor_decode[roundtrip01.json]	26.2 µs	33.5 µs	-21.84%
👁	test_dag_cbor_decode[roundtrip02.json]	26.2 µs	33.6 µs	-22.05%
👁	test_dag_cbor_decode[roundtrip05.json]	30.2 µs	37.5 µs	-19.46%
⚡	test_dag_cbor_decode[roundtrip07.json]	31.4 µs	24 µs	+30.84%
👁	test_dag_cbor_decode[roundtrip08.json]	29.4 µs	36.7 µs	-20.07%
👁	test_dag_cbor_decode[roundtrip19.json]	29.4 µs	38.1 µs	-22.75%
👁	test_dag_cbor_decode[roundtrip22.json]	28.4 µs	36.2 µs	-21.55%
👁	test_dag_cbor_decode[roundtrip23.json]	27.5 µs	34.8 µs	-20.96%

[MarshalX]

same perf. but using "match" is more rusty way imo