Cargo: align rust toolchain version with internal repository

[redsun82]

Also:

• remove new warnings raised by the rust toolchain
• run new formatting and linting
• update the rust toolchain used by cargo

While we keep bazel builds using the same toolchain as internally (now a nightly one), I opted for using a stable toolchain for cargo. The nightly toolchain is only required internally for build reasons, we should keep not using any unstable rust features in our sources.

Finally, we aren't ready yet to update the rust toolchain used in rust language tests, so I've pulled that out in its own rust-toolchain file, keeping it at 1.86 for the time being.

[Copilot]

Pull Request Overview

This PR aligns the Rust toolchain version with the internal repository by updating to a nightly toolchain for Bazel builds while using a stable toolchain for Cargo development. The changes include updating the Rust version from 1.86 to nightly/2025-08-01 for Bazel, creating a separate stable toolchain (1.88) for Cargo, and applying formatting and linting fixes required by the new toolchain.

Key changes:

• Updated Rust toolchain from stable 1.86 to nightly 2025-08-01 for Bazel builds
• Created separate toolchain configuration for Cargo using stable 1.88
• Applied formatting improvements throughout Rust codebase

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
rust-toolchain.toml	Updated to use stable Rust 1.88 for Cargo development
rust/rust-toolchain.toml	Removed (consolidated into root toolchain file)
MODULE.bazel	Updated to nightly Rust toolchain with new SHA256 hashes
.bazelrc	Added nightly toolchain configuration and linker settings
shared/tree-sitter-extractor/src/generator/ql_gen.rs	Applied lifetime annotations and formatting improvements
shared/tree-sitter-extractor/src/generator/mod.rs	Applied formatting improvements
rust/extractor/src/trap.rs	Updated string formatting to use inline syntax
rust/extractor/src/translate/base.rs	Updated string formatting to use inline syntax
rust/extractor/src/rust_analyzer.rs	Updated string formatting and added lifetime annotations
rust/ast-generator/src/main.rs	Updated string formatting and error messages

[redsun82]

@navntoft mind looking at this again? I hadn't noticed that a .gitignore rule was excluding a QL test rust-toolchain.toml that is required for Rust tests to succeed