style(clippy): fix all new clippy errors with 'rustc:1.73.0'

[woshilapin]

Description

Rust had a few new versions since the last CI job had run. Since clippy is launched with --deny warnings and new lints have been implemented since, there is few errors that any new CI job will trigger. This PR fixes all new errors due to clippy:1.73.0.

Motivation and Context

Working on #110, the CI was failing for reasons unrelated to the PR.

How Has This Been Tested?

No change of functionality, just running clippy should be enough (and the CI takes care of that).

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (no code change)
• Refactor (refactoring production code)
• Other : only stylistic changes

Checklist:

• My code follows the code style of this project.
• I have updated the documentation and changelog accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.
• Rustfmt and Rust-clippy passed.

[woshilapin]

I'm not sure what's happening on the CI, I'm not able to reproduce on my machine on nightly. However, thanks to the log, I've seen rust-lang/rust#113152 and therefore, updated proc-macro2. Let's see if this helps.

[orhun]

Great, thank you!