docs: Add general use citation from differentiable vertex fitting paper

[matthewfeickert]

Description

Add general citation from Differentiable Vertex Fitting for Jet Flavour Tagging by Rachel Smith, Inês Ochoa, Rúben Inácio, Jonathan Shoemaker, Michael Kagan.

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• Tests are passing
• "WIP" removed from the title of the pull request
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• Summarize commit messages into a comprehensive review of the PR

* Add general citation from 'Differentiable Vertex Fitting for Jet
  Flavour Tagging'.
   - c.f. https://inspirehep.net/literature/2712691

[matthewfeickert]

Relevant RTD build: https://pyhf--2355.org.readthedocs.build/en/2355/citations.html#general-citations

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (0b6e51f) 98.28% compared to head (207ecbe) 98.28%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2355   +/-   ##
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  Coverage   98.28%   98.28%           
=======================================
  Files          69       69           
  Lines        4538     4538           
  Branches      803      803           
=======================================
  Hits         4460     4460           
  Misses         45       45           
  Partials       33       33           

Flag	Coverage Δ
contrib	97.86% <ø> (ø)
doctest	60.70% <ø> (ø)
unittests-3.10	96.29% <ø> (ø)
unittests-3.11	96.29% <ø> (ø)
unittests-3.8	96.31% <ø> (ø)
unittests-3.9	96.34% <ø> (ø)

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