Add List.walk_try! #3005

Job	Run time
check-changes	20s
ran-none	0s
start-nix-linux-aarch64-build-default-test / nix-linux-arm64	36m 27s
start-nix-linux-x86-64-tests / nix-linux-x86	42m 10s
start-macos-x86-64-tests / test-rust-macos-x86-64	40m 41s
start-nix-linux-aarch64-cargo-build-test / nix-linux-arm64	44m 3s
start-nix-macos-apple-silicon-tests / nix-apple-silicon	45m 6s
start-fuzzer-tests / Fuzz test parser (allowed to fail). Do check this if you've made changes to the parser.	1m 16s
start-roc-benchmarks / benchmark roc programs	8m 25s
start-ubuntu-x86-64-nix-tests-debug / cargo test debug nix	21m 7s
start-ubuntu-x86-64-tests / test zig, rust, wasm...	29m 27s
start-windows-release-build-test / windows-release-build	13m 30s
start-windows-tests / windows-test-subset	30m 4s
ran-full	1s
finish	1s
	5h 12m 38s

Provide feedback