fix: format web3_sha3 result as an hexadecimal string

[leovct]

Motivation

The result returned by anvil web3_sha3 does not include the "0x" prefix in the hexadecimal string.

Comparing geth and anvil outputs, with the same parameter, we can see the difference:

# geth result
$ curl -H 'Content-Type: application/json' -d '{"jsonrpc": "2.0", "method": "web3_sha3", "params": ["0x68656c6c6f20776f726c64"], "id": 74}' http://localhost:8545
{"jsonrpc":"2.0","id":74,"result":"0x47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad"}

# anvil result
$ curl -H 'Content-Type: application/json' -d '{"jsonrpc": "2.0", "method": "web3_sha3", "params": ["0x68656c6c6f20776f726c64"], "id": 74}' http://localhost:8545
{"jsonrpc":"2.0","id":74,"result":"47173285a8d7341e5e972fc677286384f802f8ef42a5ec5f03bbfa254cb01fad"}

Solution

Add the 0x prefix to the result of sha3.

[Evalir]

lgtm, just nit