mathjax loading on per page basis causes issue for nodes containing math in reference only #40

Describe the problem

It looks like mathjax doesn't get loaded by sphinx on page that contains nodes that reference math but don't explicitly include math on that page

For example:

.. solution:: exercise-1
    :label: solution-1

    This is a solution to exercise 1

references

.. exercise:: :math:`n!` factorial
    :label: exercise-1

    Exercise 1 about :math:`n!` factorial

But will result in:

but if you add a math role anywhere on that page it will be correctly rendered.

Link to your repository or website

No response

Steps to reproduce

1. Have a page with solution nodes only with references to exercise nodes that contain math in the titles

The version of Python you're using

No response

Your operating system

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Versions of your packages

No response

Additional context

I suspect this relates to loading mathjax on a per page basis

sphinx-doc/sphinx#9686