Better way of specifying `nibble_list_to_compact`

[lightclient]

This seems a bit more readable way of specifying this?

https://github.com/ethereum-optimism/optimism/blob/d040a8d972fe1d25ccbb0dc8223a19d7eb1656b1/packages/contracts/contracts/libraries/trie/Lib_MerkleTrie.sol#L44-L47