feat: handle echo as shell built-in #49

Job	Run time
Test (ubuntu-latest, x86_64-unknown-linux-gnu)	1m 53s
Test (namespace-profile-mac-default, aarch64-apple-darwin)	36s
Lint	1m 33s
Test (windows-latest, x86_64-pc-windows-msvc)	2m 50s
done	3s
	6m 55s

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