Rust 1.81

[rukai]

Updates to rust 1.81 and fixes some clippy lints that were introduced in 1.81

This PR also makes use of some new features in 1.81:

• Some existing allow lints are turned into expect lints, this means that if the allow is no longer needed a warning will occur and the allow alerting the developer to remove the allow
• existing comments explaining why we have lints are turned into lint reasons
  • The new lint reason field is really cool, for example now that we have a lint reason for deny unsafe, we get these error messages including the lint reason if we attempt to use an unsafe block. (see below image)

[codspeed-hq]

CodSpeed Performance Report

Merging #1746 will not alter performance

_{Comparing rukai:rust_1.81 (d3c99d3) with main (e94328d)}

Summary

✅ 39 untouched benchmarks