Fix typos in arviz codebase

[hectormz]

Description

This PR fixes typos in arviz with the help of codespell.

There was no Issue preceding this PR. I would normally create an issue for a more significant change first. There may be other typos still in arviz that codespell didn't pick up.

Most typos are in comments, but there is one in a variable name, and in an exception message.

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Codecov Report

Merging #1700 (f611882) into main (1a39374) will not change coverage.
The diff coverage is 85.71%.

❗ Current head f611882 differs from pull request most recent head 0eb561e. Consider uploading reports for the commit 0eb561e to get more accurate results

@@           Coverage Diff           @@
##             main    #1700   +/-   ##
=======================================
  Coverage   90.86%   90.86%           
=======================================
  Files         108      108           
  Lines       11818    11818           
=======================================
  Hits        10738    10738           
  Misses       1080     1080           

Impacted Files	Coverage Δ
arviz/data/datasets.py	98.38% <ø> (ø)
arviz/data/inference_data.py	83.57% <ø> (ø)
arviz/data/io_numpyro.py	93.89% <ø> (ø)
arviz/data/io_pystan.py	96.08% <ø> (ø)
arviz/plots/backends/bokeh/jointplot.py	98.24% <0.00%> (ø)
arviz/plots/forestplot.py	94.59% <ø> (ø)
arviz/plots/jointplot.py	96.29% <ø> (ø)
arviz/plots/kdeplot.py	100.00% <ø> (ø)
arviz/plots/khatplot.py	94.87% <ø> (ø)
arviz/plots/plot_utils.py	86.59% <ø> (ø)
... and 7 more

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