refactor(error): remove unused Listen variant #2118

Job	Run time
Check Style	7s
Verify hyper.h is up to date	46s
features	40s
Test stable on ubuntu-latest	2m 0s
Test stable on windows-latest	4m 8s
Test stable on macOS-latest	2m 24s
Test beta on ubuntu-latest	2m 0s
Test beta on windows-latest	4m 21s
Test beta on macOS-latest	2m 39s
Test nightly on ubuntu-latest	2m 10s
Test nightly on windows-latest	3m 36s
Test nightly on macOS-latest	3m 3s
Test with Miri	1m 15s
Test C API (FFI)	55s
Check MSRV	2m 49s
Build docs	28s
CI is green	1s
	33m 22s

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