test: pass clippy test on latest stable toolchain (#1008)

[MrCroxx]

What's changed and what's your intention?

Please explain IN DETAIL what the changes are in this PR and why they are needed. :D

Cherry pick 4 commits:

• deff393
• 08844ad
• aca8531
• 77a7607

Checklist

• I have written the necessary rustdoc comments
• I have added the necessary unit tests and integration tests
• I have passed make all (or make fast instead if the old tests are not modified) in my local environment.

Related issues or PRs (optional)

#1008 #1007 #1012 #1013 #1011

[codecov]

Codecov Report

Attention: Patch coverage is 97.36842% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
foyer-memory/src/cache.rs	50.00%	1 Missing ⚠️

Files with missing lines	Coverage Δ
foyer-common/src/code.rs	87.20% <ø> (ø)
foyer-memory/src/raw.rs	90.14% <100.00%> (+0.60%)	⬆️
foyer-storage/src/large/generic.rs	86.44% <100.00%> (+0.03%)	⬆️
foyer/src/hybrid/builder.rs	93.81% <100.00%> (ø)
foyer/src/hybrid/cache.rs	86.60% <100.00%> (+3.54%)	⬆️
foyer/src/hybrid/writer.rs	97.29% <ø> (ø)
foyer-memory/src/cache.rs	79.26% <50.00%> (ø)

... and 2 files with indirect coverage changes

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