fix(packages): Correct math greek symbols and their var-alternate

[Omikhleia]

Closes #2134

Or does it? Who knows, it breaks test tests/math-bigops.xml due to the bogus epsilon. Surely whoever wrote this test checked again LaTeX, right?

EDIT: For the record, Typst deviates slightly from LaTeX https://qwinsi.github.io/tex2typst-webapp/cheat-sheet.html

• It has the \varxxx.. symbols as xxx.alt
• Except that epsilon and phi are inverted (the .alt variants are the non-var ones)

[OlivierNicole]

Or does it? Who knows, it breaks test tests/math-bigops.xml due to the bogus epsilon. Surely whoever wrote this test checked again LaTeX, right?

I don’t remember, but it wasn’t deeply thought out. I think you should modify the test reference based on the decision that you take regarding the symbol names.

[Omikhleia]

Fixed the broken test to use \varepsilon for ε, in compliance with TeX math's expectations (= output unchanged, an inline with the MathML case which uses an explicit ε).