validate_docstrings improvements

[kynan]

Some minor improvments to validate_docstrings:

• outputs warning/error codes in the list of validations
• add --list-errors flag to list error codes / descriptions

[WillAyd]

Thanks for the PR.

• Is this closing an open issue that has been discussed?
• Can you add tests?

[codecov]

Codecov Report

Merging #25122 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #25122      +/-   ##
==========================================
+ Coverage   92.37%   92.37%   +<.01%     
==========================================
  Files         166      166              
  Lines       52415    52415              
==========================================
+ Hits        48418    48419       +1     
+ Misses       3997     3996       -1

Flag	Coverage Δ
#multiple	90.79% <ø> (ø)	⬆️
#single	42.86% <ø> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/core/frame.py	96.82% <0%> (ø)	⬆️
pandas/core/arrays/categorical.py	95.97% <0%> (ø)	⬆️
pandas/core/window.py	96.4% <0%> (ø)	⬆️
pandas/util/testing.py	88.13% <0%> (+0.09%)	⬆️

---

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[codecov]

Codecov Report

Merging #25122 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #25122      +/-   ##
==========================================
+ Coverage   92.37%   92.37%   +<.01%     
==========================================
  Files         166      166              
  Lines       52415    52415              
==========================================
+ Hits        48418    48419       +1     
+ Misses       3997     3996       -1

Flag	Coverage Δ
#multiple	90.79% <ø> (ø)	⬆️
#single	42.86% <ø> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/core/frame.py	96.82% <0%> (ø)	⬆️
pandas/core/arrays/categorical.py	95.97% <0%> (ø)	⬆️
pandas/core/window.py	96.4% <0%> (ø)	⬆️
pandas/util/testing.py	88.13% <0%> (+0.09%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[datapythonista]

I would avoid all these changes based on personal preference. It just adds noise to keep changing tabs by spaces in the output, or adding line breaks to function calls. The code is respecting PEP8, and if every person reformats based on his personal preference, we'll change those at every PR.

Can you revert those, leave the relevant part of the PR, and fix the problems in the CI please?

[WillAyd]

Closing for now due to failures and comments above. If you want to pursue further please open an issue first for discussion