julia

5e4e7fa1 - remove unnecessary `\up` (upright) from some latex abbrevs (e.g. \upMu -> \Mu) (#50925)

remove unnecessary `\up` (upright) from some latex abbrevs (e.g. \upMu -> \Mu) (#50925) Closes #50911. Closes #50913. There were a few oddball symbols prefixed with `\up` (for "upright") for no reason that I can tell, ala the LaTeX "upgreek" package, even though we don't use an `\up` prefix for other upright Greek letters (e.g. we have `\alpha`, not `\upalpha`, even though it isn't italicized — we have `\italpha` for italic alpha). Not breaking since this is just a UI thing. (In practice, I doubt many people use these symbols. e.g. `\upMu` is `Μ`, which looks a lot like the Latin `M`. But there is no reason to have the `\up` prefix here. It seems to have just been an automated abbreviation-import snafu. And [`\upkoppa 'ϟ'` (U+O3DF)](https://www.compart.com/en/unicode/U+03DF) is visually quite distinctive though I've never seen it used in math, not to mention lowercase — it's definitely goofy to have an `\up` prefix for it.)