Fix typos in documentation

[seunghwak]

Fix few typos in documentation.

[codecov-commenter]

Codecov Report

Merging #2225 (42f0167) into branch-22.06 (38be932) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@               Coverage Diff                @@
##           branch-22.06    #2225      +/-   ##
================================================
+ Coverage         70.82%   70.86%   +0.04%     
================================================
  Files               170      170              
  Lines             11036    11036              
================================================
+ Hits               7816     7821       +5     
+ Misses             3220     3215       -5     

Impacted Files	Coverage Δ
python/cugraph/cugraph/structure/hypergraph.py	90.00% <100.00%> (ø)
.../cugraph/tests/test_edge_betweenness_centrality.py	84.93% <0.00%> (+0.60%)	⬆️
...graph/cugraph/tests/test_betweenness_centrality.py	83.01% <0.00%> (+0.62%)	⬆️
python/cugraph/cugraph/tests/test_graph_store.py	100.00% <0.00%> (+1.56%)	⬆️
python/cugraph/cugraph/tests/test_utils.py	75.55% <0.00%> (+4.44%)	⬆️

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[ChuckHastings]

@gpucibot merge