MINOR: Fix clippy for rust 1.64.0

[viirya]

Which issue does this PR close?

Rationale for this change

Fixing a clippy error for rust 1.64.0 in CI:

error: this expression borrows a value the compiler would automatically borrow
   --> arrow-buffer/src/util/bit_chunk_iterator.rs:181:5
    |
181 |     (&mut buf[..len]).copy_from_slice(input);
    |     ^^^^^^^^^^^^^^^^^ help: change this to: `buf[..len]`
    |
    = note: `-D clippy::needless-borrow` implied by `-D warnings`
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow

What changes are included in this PR?

Are there any user-facing changes?

[viirya]

cc @tustvold @sunchao

[viirya]

Thanks.

[ursabot]

Benchmark runs are scheduled for baseline = 9833d29 and contender = c2972c1. c2972c1 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ec2-t3-xlarge-us-east-2] ec2-t3-xlarge-us-east-2
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on test-mac-arm] test-mac-arm
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ursa-i9-9960x] ursa-i9-9960x
[Skipped ⚠️ Benchmarking of arrow-rs-commits is not supported on ursa-thinkcentre-m75q] ursa-thinkcentre-m75q
Buildkite builds:
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python, R. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java