rename CorrCoef

[Borda]

What does this PR do?

For consistency keep camel case strict corrcoef -> CorrCoef as it it Correlation Coerficient
part of #729

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• Did you make sure to update the docs?
• Did you write any new necessary tests?

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[codecov]

Codecov Report

Merging #710 (f7c9cbd) into master (89f603b) will decrease coverage by 0%.
The diff coverage is 90%.

@@          Coverage Diff          @@
##           master   #710   +/-   ##
=====================================
- Coverage      95%    95%   -0%     
=====================================
  Files         166    166           
  Lines        6424   6439   +15     
=====================================
- Hits         6117   6110    -7     
- Misses        307    329   +22