Remove the blanket implementation for reference of `Automaton` #1952

Job	Run time
rustfmt	4s
test (pinned, ubuntu-latest, 1.60.0)	3m 28s
test (stable, ubuntu-latest, stable)	1m 3s
test (stable-x86, ubuntu-latest, stable, i686-unknown-linux-gnu)	1m 7s
test (stable-aarch64, ubuntu-latest, stable, aarch64-unknown-linux-gnu)	7m 54s
test (stable-powerpc64, ubuntu-latest, stable, powerpc64-unknown-linux-gnu)	4m 41s
test (stable-s390x, ubuntu-latest, stable, s390x-unknown-linux-gnu)	5m 49s
test (beta, ubuntu-latest, beta)	1m 0s
test (nightly, ubuntu-latest, nightly)	1m 1s
test (macos, macos-latest, stable)	57s
test (win-msvc, windows-latest, stable)	3m 0s
test (win-gnu, windows-latest, stable-x86_64-gnu)	2m 12s
	32m 16s

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