Fuzz

Merge rust-bitcoin/rust-miniscript#642: Remove generics from Error by… #329

Job	Run time
fuzz (roundtrip_semantic)	4m 56s
fuzz (parse_descriptor)	4m 49s
fuzz (parse_descriptor_secret)	5m 39s
fuzz (roundtrip_miniscript_script)	4m 45s
fuzz (roundtrip_miniscript_str)	5m 0s
fuzz (roundtrip_descriptor)	4m 52s
fuzz (roundtrip_concrete)	4m 54s
fuzz (compile_descriptor)	4m 52s
verify-execution	10s
	39m 57s

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