fix: Build docs without parallelization to fix pop-up issues with sphinx-tippy

[nfelt14]

Proposed changes

Run doc building without parallelization to try to work around a bug in sphinx-tippy.

Types of changes

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• Bug fix (non-breaking change which fixes an issue)
• Documentation update (an update to enhance the user experience when reading through the docs)

Checklist

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[codecov]

Codecov Report

Merging #80 (6d5a34c) into main (e01e099) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main       #80   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files          168       168           
  Lines         3768      3768           
  Branches       646       646           
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  Hits          3768      3768           

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[nfelt14]

A normal doc build used to take about 45 minutes, but the pop-ups were non-functional. Now the build takes 65 minutes, but the pop-ups are functional.

[nfelt14]

This PR works around this issue: sphinx-extensions2/sphinx-tippy#9