Zebra: Tracking: require docs in all Zebra modules

[teor2345]

Some Zebra modules have !#[deny(missing_docs)], and some don't.

Let's require docs in all modules, so we don't forget to document our code:

• [ ] tower-batch
• [ ] tower-fallback
• [x] zebra-chain
• [ ] zebra-client
• [ ] zebra-consensus
• [x] zebra-network
• [ ] zebra-rpc
• [ ] zebra-script
• [ ] zebra-state
• [ ] zebra-test
• [x] zebra-utils
• [ ] zebrad

[yaahc]

Similarly, I think it might be a good idea to go over the available lints provided by rustc and clippy as part of a gardening session from time to time to see if there are other lints we'd want to enable across all our crates.

[teor2345]

Similarly, I think it might be a good idea to go over the available lints provided by rustc and clippy as part of a gardening session from time to time to see if there are other lints we'd want to enable across all our crates.

Do we have a TODO list for gardening?
Or a rotating list?

If not, let's start one.

[teor2345]

Un-checked zebra-consensus, because we stopped requiring docs in #1043.