Fix clippy and fmt issues

[iamnotacake]

New clippy, new issues that make working code fail CI checks. Again.

Fixed clippy issues with cargo clippy --fix --all-targets, the formatted with cargo fmt.

Only cosmetic changes, most of them are outside of wrapper, i.e. in tests and benchmarks.

Update MSRV to 1.60 since our dependency zeroize now requires it.

Freeze two more dev deps regex and memchr, dependencies of env_logger used in Rust Themis tests.

Checklist

• [x] Change is covered by automated tests
• [x] ~Benchmark results are attached (if applicable)~
• [x] The coding guidelines are followed
• [x] ~Public API has proper documentation~
• [x] ~Example projects and code samples are up-to-date (in case of API changes)~
• [x] ~Changelog is updated (in case of notable or breaking changes)~

[vixentael]

Uh..

error: package `zeroize v1.7.0` cannot be built because it requires rustc 1.60 or newer, while the currently active rustc version is 1.58.1```

[iamnotacake]

error: package zeroize v1.7.0 cannot be built because it requires rustc 1.60 or newer

Well, there are two-and-a-half possible solutions: 1) Simply freeze zeroize version like I did with some other test deps that require newer compiler; basically, it's all about tests, and Themis itself does not require newer compiler 2) Update MSRV to 1.60 (released on April 2022 btw) and solve this issue 2.5) Update MSRV even more (something like 1.63?) to also remove other frozen deps, solve all issues until some deps will update again and will require even newer toolchain, but that's in future

[vixentael]

i vote for (1), @Lagovas WDYT?

[Lagovas]

I vote for both cases. Freeze and update, because I see, that a lot of dependencies upgraded their dependencies (it's 3th or 4th issue like that0