🐛 FIX: Update priority for LaTeX output for html and latex builders

[mmcky]

This PR increases the priority for text/latex representations for html and latex builders.

For html -- mathjax renders the text/latex representation more cleanly than typical images provided by some underlying packages (i.e. for png images) so promoted to be below image/svg+xml but above other image types.

For latex -- native latex syntax should be used in preference.

[mmcky]

• check if this PR fixes [jupyterbook-latex] [re_with_feedback] problematic math outputs generated by code QuantEcon/lecture-python.myst#95
• fix fixtures (the unknown mimtype fixture is removed as that test is current commented out in test_render_outputs.py)

[chrisjsewell]

I don't think latex should be above svg

[codecov]

Codecov Report

Merging #305 (37d949b) into master (2baade0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #305   +/-   ##
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  Coverage   87.35%   87.35%           
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  Files          12       12           
  Lines        1368     1368           
=======================================
  Hits         1195     1195           
  Misses        173      173           

Flag	Coverage Δ
pytests	87.35% <ø> (ø)

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Impacted Files	Coverage Δ
myst_nb/render_outputs.py	86.79% <ø> (ø)

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[mmcky]

I don't think latex should be above svg

hey @chrisjsewell can you explain why? (i.e. page load times?) mathjax seems to do a nicer job of displaying the math. I am certainly open to demoting below svg but just want to understand why you think that is a better default priority.

For latex I think it certainly should be the highest output priority for native rendering.

[chrisjsewell]

Because svg is natively supported by HTML, latex is not

[mmcky]

Because svg is natively supported by HTML, latex is not

roger that.

[mmcky]

@chrisjsewell I see epub is listed as a builder in the builder option list.

Do you know if epub has a mechanism to support text/latex like mathjax for html?

Hmm -- I think epub uses mathml for math but also supports svg natively so another good reason to promote image/svg+xml. I guess the question is what happens if latex is passed before png.

Open to suggestions but perhaps we should:

• create a default priority for html based builders
• create a default priority for epub builder (separate like LaTeX)

[bsipocz]

A lot of the code has been refactored from underneath this PR so I'm inclined to close it for now.

If you would be interested to reopen the PR on top of the latest master branch I am happy to do a quick review and merge.