ARROW-12047: [Rust] [Parquet] Cleanup clippy

[jorgecarleitao]

No description provided.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-12047

[codecov-io]

Codecov Report

Merging #9775 (cd369c9) into master (29feea0) will decrease coverage by 0.32%.
The diff coverage is 81.29%.

@@            Coverage Diff             @@
##           master    #9775      +/-   ##
==========================================
- Coverage   82.59%   82.27%   -0.33%     
==========================================
  Files         248      249       +1     
  Lines       58294    58359      +65     
==========================================
- Hits        48149    48013     -136     
- Misses      10145    10346     +201     

Impacted Files	Coverage Δ
rust/arrow/src/compute/kernels/take.rs	96.06% <ø> (-0.01%)	⬇️
rust/arrow/src/compute/kernels/window.rs	100.00% <ø> (ø)
rust/arrow/src/compute/kernels/zip.rs	82.14% <ø> (ø)
rust/arrow/src/compute/util.rs	98.92% <ø> (ø)
rust/arrow/src/ffi.rs	76.22% <ø> (ø)
rust/arrow/src/ipc/reader.rs	84.36% <ø> (ø)
rust/arrow/src/ipc/writer.rs	87.44% <ø> (+0.21%)	⬆️
rust/arrow/src/json/reader.rs	83.45% <ø> (-0.06%)	⬇️
rust/arrow/src/json/writer.rs	87.91% <ø> (ø)
rust/arrow/src/record_batch.rs	83.70% <ø> (ø)
... and 82 more

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[alamb]

Looks like a nice improvement to me. Thanks @jorgecarleitao

[Dandandan]

Looks good!

[nevi-me]

LGTM