Document view state proofs

[mina86]

#7603 added include_proof option to view_state RPC request. Once 1.30 hits mainnet, this option needs to be documented. Furthermore, we also need to document format of the proof.

• Release 1.30 to mainnet
• Document include_proof in docs repository.
• Document how to verify proof.

Documenting include_proof just means mentioning that it’s an optional argument and if it’s set to true the proof in response will be populated. Documenting how to verify proofs is a bit more work and may require touching Nomicon to document format of the trie.

I’m going to mark this as C-good-first-issue because I think this may be a good first issue for anyone who’d like to dig into how the state is stored in the trie without having to write any code.