Add comments everywhere that C and Rust must stay in sync

There are places in protover.rs where, if we were to change our C code without a corresponding change, we could break things. We should mark the C and the Rust code in all of those places.

changed milestone to %Tor: 0.3.3.x-final in legacy/trac

added component::core tor/tor in Legacy / Trac doc in Legacy / Trac milestone::Tor: 0.3.3.x-final in Legacy / Trac owner::chelseakomlo in Legacy / Trac priority::high in Legacy / Trac resolution::implemented in Legacy / Trac rust in Legacy / Trac severity::normal in Legacy / Trac status::closed in Legacy / Trac type::defect in Legacy / Trac labels

Trac:
Status: new to assigned
Owner: N/A to chelseakomlo

See git@github.com:chelseakomlo/tor_patches.git, branch 24032-cargo-rust-sync. I can make a PR in oniongit if that makes review easier; these are all documentation changes.

I annotated only where data needs to stay in sync (such as enums and constants). If we change actual logic/behavior in src/or/protover, src/rust/protover will definitely need to change as well. I can put a comment in src/rust/protover/lib.rs to say that the overall module needs to track the C implementation if that would be helpful.

Trac:
Status: assigned to needs_review

Merged! I've also added corresponding comments in the C code, and a suggestion to do it in both places in the future. (Rationale: if the dependency is undocumented at either location, then it's likelier that somebody will edit that location without noticing the dependency.)

Trac:
Resolution: N/A to implemented
Status: needs_review to closed

closed

moved from legacy/trac#24032 (moved)

added Bug label and removed 1 deleted label

added Rust + 1 deleted label and removed 1 deleted label

added Documentation label and removed 1 deleted label