Fix warnings in cargo doc

[alamb]

Which issue does this PR close?

Closes #1267

Rationale for this change

Non broken links are nice!

See #1266 for CI check

What changes are included in this PR?

Run

 cargo doc --document-private-items --no-deps --workspace --

Until it is clean

Are there any user-facing changes?

Doc links work better

[codecov-commenter]

Codecov Report

Merging #1268 (981a118) into master (43299cc) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1268      +/-   ##
==========================================
- Coverage   83.02%   83.02%   -0.01%     
==========================================
  Files         180      180              
  Lines       52269    52269              
==========================================
- Hits        43398    43396       -2     
- Misses       8871     8873       +2     

Impacted Files	Coverage Δ
arrow/src/array/array_list.rs	95.52% <ø> (ø)
arrow/src/array/array_map.rs	81.50% <ø> (ø)
arrow/src/array/array_union.rs	90.76% <ø> (ø)
arrow/src/array/data.rs	83.02% <ø> (ø)
arrow/src/array/mod.rs	100.00% <ø> (ø)
arrow/src/array/raw_pointer.rs	100.00% <ø> (ø)
arrow/src/array/transform/mod.rs	84.64% <ø> (ø)
arrow/src/bytes.rs	56.25% <ø> (ø)
arrow/src/compute/kernels/partition.rs	97.45% <ø> (ø)
arrow/src/compute/kernels/sort.rs	95.13% <ø> (ø)
... and 8 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 43299cc...981a118. Read the comment docs.