DOC: Remove doc spellcheck

[datapythonista]

The spellcheck system was implemented, but with dependencies (i.e. enchant) that are no longer maintained, and there is no reasonable way to set them up. This means that can't be added to the CI, and can't be even set up into our local environments with a decent amount of work installing dependencies manually (I didn't succeed).

The PR that was trying to finish the work on the spellcheck, #21402, was finally discarded, but part of the stuff is still in sphinx, just generating a warning when trying to get the sphinx extension.

This PR removes it.

[pep8speaks]

Hello @datapythonista! Thanks for submitting the PR.

• There are no PEP8 issues in the file doc/make.py !

• There are no PEP8 issues in the file doc/source/conf.py !

[codecov]

Codecov Report

Merging #24287 into master will decrease coverage by 49.21%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master   #24287       +/-   ##
===========================================
- Coverage   92.22%      43%   -49.22%     
===========================================
  Files         162      162               
  Lines       51824    51824               
===========================================
- Hits        47795    22289    -25506     
- Misses       4029    29535    +25506

Flag	Coverage Δ
#multiple	?
#single	43% <ø> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/io/formats/latex.py	0% <0%> (-100%)	⬇️
pandas/core/categorical.py	0% <0%> (-100%)	⬇️
pandas/io/sas/sas_constants.py	0% <0%> (-100%)	⬇️
pandas/tseries/plotting.py	0% <0%> (-100%)	⬇️
pandas/tseries/converter.py	0% <0%> (-100%)	⬇️
pandas/io/formats/html.py	0% <0%> (-98.65%)	⬇️
pandas/core/groupby/categorical.py	0% <0%> (-95.46%)	⬇️
pandas/io/sas/sas7bdat.py	0% <0%> (-91.17%)	⬇️
pandas/io/sas/sas_xport.py	0% <0%> (-90.15%)	⬇️
pandas/core/tools/numeric.py	10.44% <0%> (-89.56%)	⬇️
... and 119 more

---

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[codecov]

Codecov Report

Merging #24287 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #24287   +/-   ##
=======================================
  Coverage   92.22%   92.22%           
=======================================
  Files         162      162           
  Lines       51824    51824           
=======================================
  Hits        47795    47795           
  Misses       4029     4029

Flag	Coverage Δ
#multiple	90.62% <ø> (ø)	⬆️
#single	43.01% <ø> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7b0fa8e...65b7493. Read the comment docs.

[jreback]

thanks!

[jreback]

can you do a followup to remove sphinxcontrib-spelling from any of the ci & environment.yml & also remove the spelling section from the contributing guide. thanks.

[datapythonista]

Thanks for pointing out @jreback, I totally forgot about it (and I double checked, and there were also some code left in doc/make.py I wasn't aware of).

I opened this follow up: #24299