Merge rust-bitcoin/rust-bitcoin#2746: hashes: Modify trait bounds #6814

Job	Run time
Prepare	5s
Test - stable toolchain (minimal)	13m 28s
Test - stable toolchain (recent)	12m 38s
Docs - stable toolchain (recent)	35s
Test 32-bit version	51s
Cross test - stable toolchain	1m 36s
Kani codegen - stable toolchain	50s
Test - 1.56.1 toolchain (minimal)	20m 23s
Test - 1.56.1 toolchain (recent)	19m 57s
Schemars - stable toolchain (recent)	26s
WASM - stable toolchain	1m 38s
Test - nightly toolchain (minimal)	12m 55s
Bench - nightly toolchain (recent)	1m 6s
Test - nightly toolchain (recent)	13m 16s
Docs - nightly toolchain (recent)	36s
ASAN - nightly toolchain (recent)	37s
Lint - nightly toolchain (recent)	1m 9s
Embedded - nightly toolchain	1m 21s
	1h 43m 27s

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