INTERACTIVE SICP-JS: Switch math parsing library to KaTeX

[samuelfangjw]

Description

This PR replaces the current MathJax based library (better-react-mathjax) with a KaTeX based library react-latex-next.

This change results in a huge speedup, with most pages loading almost instantly now. For comparison, new library on left and old library on right. (I haven't pulled the latest changes for the older version, so the font looks a bit smaller).

Screen.Recording.2021-06-17.at.10.31.48.PM.mov

Downsides: React KaTeX does not support all the features of MathJax. However, we can circumvent this by replacing tags in the JSON files that are not recognised with ones that are see this PR.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Code quality improvements

How to test

Check that math equations are parsed properly.

Checklist

• I have tested this code
• I have updated the documentation

[coveralls]

Pull Request Test Coverage Report for Build 946836761

• 7 of 8 (87.5%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.01%) to 30.167%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/pages/sicp/Sicp.tsx	1	2	50.0%

Totals
Change from base Build 946733930:	-0.01%
Covered Lines:	3229
Relevant Lines:	9871

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💛 - Coveralls

[martin-henz]

looks gook