bazel: cargo-gazelle fix rust_binary name collision, upgrade Rust version

[ParkMyCar]

It's relatively common for Rust library targets and binary targets to have the same name, e.g. when you have a lib.rs and a main.rs. cargo-gazelle had some automatic detection for this, but it looks like it broke after the most recent Rust upgrade because Cargo changed from a snake_case default to kebab-case.

This PR changes the name collision detection to explicitly use snake_case. It also updates the version of Rust that Bazel uses to be the same as the default one we build with.

Motivation

Fixes cargo-gazelle

Checklist

• This PR has adequate test coverage / QA involvement has been duly considered. (trigger-ci for additional test/nightly runs)
• This PR has an associated up-to-date design doc, is a design doc (template), or is sufficiently small to not require a design.
• If this PR evolves an existing $T ⇔ Proto$T mapping (possibly in a backwards-incompatible way), then it is tagged with a T-proto label.
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• This PR includes the following user-facing behavior changes:
  • N/a