Fix some doxygen warnings and add missing documentation

[karthikeyann]

fix to ignore __device__ void return type warnings.
add missing documentation on some functions
Correct doxygen doc style comment fixes

[codecov]

Codecov Report

Merging #9770 (20ddd3d) into branch-22.02 (967a333) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

❗ Current head 20ddd3d differs from pull request most recent head 1602867. Consider uploading reports for the commit 1602867 to get more accurate results

@@               Coverage Diff                @@
##           branch-22.02    #9770      +/-   ##
================================================
- Coverage         10.49%   10.47%   -0.02%     
================================================
  Files               119      119              
  Lines             20305    20332      +27     
================================================
  Hits               2130     2130              
- Misses            18175    18202      +27     

Impacted Files	Coverage Δ
python/cudf/cudf/core/column/column.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/frame.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/index.py	0.00% <ø> (ø)
python/cudf/cudf/core/indexed_frame.py	0.00% <0.00%> (ø)
python/cudf/cudf/core/multiindex.py	0.00% <0.00%> (ø)
python/cudf/cudf/utils/utils.py	0.00% <0.00%> (ø)
python/cudf/cudf/_fuzz_testing/fuzzer.py	0.00% <0.00%> (ø)
python/cudf/cudf/utils/hash_vocab_utils.py	0.00% <0.00%> (ø)

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[karthikeyann]

rerun tests

[karthikeyann]

@gpucibot merge