Add comment to some params that need to be hex encoded

[Albermonte]

The params are:

• data from TransactionParams
• signalData from NewValidatorTxParams
• newSignalData from UpdateValidatorTxParams

The RPC would only accept an encoded hex string instead a UTF-8 string

[onmax]

What's the difference between hex and string?

Hex starting with 0x? Should the lib make some parser to uint array or any other format?

[Albermonte]

The RPC node only accepts an hex string, if you send any other string it will fail to decode it. You can convert a string to an hex string with Buffer.from("blablabla").toString("hex")