Improving RPC doc comments - addresses #339

[elielnfinic]

Improving RPC doc comments - addresses #339

[dan-da]

thx for the PR.

small nit: I would say it addresses #339, not fixes it. That's because we divided it into two parts. Please edit the description of this PR, otherwise I believe github may automatically close #339 when this gets merged.

[dan-da]

Thanks for the PR @elielnfinic, it's a good start.

Please make the changes I suggested in the comments and ensure that cargo test --doc executes cleanly without warnings/errors.

Also, please squash all the commits into one.
https://www.baeldung.com/ops/git-squash-commits

with that, I think we will be ready to merge it.

let me know if any q's or concerns.

[dan-da]

Ler's keep these examples focused on just the RPC call that is being documented. example:

    /// ```no_run
    /// # use neptune_cash::rpc_server::RPCClient;
    /// # use neptune_cash::rpc_auth;
    /// # use tarpc::tokio_serde::formats::Json;
    /// # use tarpc::serde_transport::tcp;
    /// # use tarpc::client;
    /// # use tarpc::context;
    ///
    /// # tokio_test::block_on(async {
    ///
    /// # let transport = tcp::connect("127.0.0.1:9799", Json::default).await.unwrap();
    /// # let client = RPCClient::new(client::Config::default(), transport).spawn();
    ///
    /// // query neptune-core server how to find the cookie file
    /// let cookie_hint = client.cookie_hint(context::current()).await.unwrap().unwrap();
    ///
    /// # })
    /// ```

The module level doc-comment already provides a full example showing use statements and how to instantiate rpc client and obtain auth token.

[dan-da]

also, can we use ?? instead of .unwrap().unwrap()?

[dan-da]

I don't see cookie_hint defined. Does this actually compile? I think you are missing a call like:

    let cookie_hint = client.cookie_hint(context::current()).await??;

anyway, let's comment out all the setup stuff, so only the RPC call displays in the generated docs.

also, please replace the unwrap() with ? if possible.