Make diagram and caption consistent in Pagerank.ipynb

[charlesbluca]

Fixes some small inconsistencies between code blocks / diagrams and their associated captions in the Pagerank notebook. We might want to resolve the FutureWarning raised in from_cudf_edgelist first, as it crops up in the outputs (xref #2174).

Closes #2182

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Codecov Report

Merging #2207 (9714431) into branch-22.06 (38be932) will increase coverage by 0.04%.
The diff coverage is n/a.

@@               Coverage Diff                @@
##           branch-22.06    #2207      +/-   ##
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+ Coverage         70.82%   70.86%   +0.04%     
================================================
  Files               170      170              
  Lines             11036    11036              
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+ Hits               7816     7821       +5     
+ Misses             3220     3215       -5     

Impacted Files	Coverage Δ
.../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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[BradReesWork]

@gpucibot merge