Improve code formatting in docstrings

[flukeskywalker]

How about using blacken-docs as a pre-commit hook as I did here? If it's too annoying we can remove it but still keep the formatted code, and manually control formatting going forward.

[codecov-commenter]

Codecov Report

Merging #3 (8daf2fc) into master (fb71a8a) will increase coverage by 0.02%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master       #3      +/-   ##
==========================================
+ Coverage   50.51%   50.53%   +0.02%     
==========================================
  Files          33       33              
  Lines        4702     4704       +2     
==========================================
+ Hits         2375     2377       +2     
  Misses       2327     2327              

Impacted Files	Coverage Δ
src/evotorch/neuroevolution/neproblem.py	33.73% <ø> (ø)
src/evotorch/neuroevolution/net/parser.py	17.85% <ø> (ø)
src/evotorch/neuroevolution/supervisedne.py	34.92% <ø> (+0.54%)	:arrow_up:
src/evotorch/tools/objectarray.py	64.59% <ø> (ø)
src/evotorch/neuroevolution/gymne.py	27.50% <0.00%> (+0.59%)	:arrow_up:

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[flukeskywalker]

Ready for review again

[flukeskywalker]

@Higgcz ready to merge