chore: Update MathJax path for Sphinx documentation

[LacombeLouis]

Description

Change in the mathjax_path for the sphinx configuration, #480.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• [ ] Check that the documentation and mathematical notations builds correctly.

Checklist

• [x] I have read the contributing guidelines
• [ ] I have updated the HISTORY.rst and AUTHORS.rst files
• [x] Linting passes successfully : make lint
• [x] Typing passes successfully : make type-check
• [x] Unit tests pass successfully : make tests
• [x] Coverage is 100% : make coverage
• [ ] Documentation builds successfully : make doc