feat(typst): add support for loading symbol mappings from Typst codex crate

[Bnyro]

This PR adds support for the symbols from https://github.com/typst/codex.

Stats:

1. Iterating over all Typst codex symbols gives us 997 symbols, although there are more than 1.3k in https://raw.githubusercontent.com/typst/codex/refs/heads/main/src/modules/sym.txt?
2. We can successfully map around 270 symbols from Typst codex to Latex commands using Unicode
3. In the end, we get 127 new symbols that aren't already covered by other sources

So there's a lot of loss in steps 1 and 2 - I'm not really sure why. Some of it is because Typst codex includes a lot of emojis that don't have any latex commands, but still we're loosing a lot of commands :/

[FineFindus]

Thanks.

Iterating over all Typst codex symbols gives us 997 symbols, although there are more than 1.3k in https://raw.githubusercontent.com/typst/codex/refs/heads/main/src/modules/sym.txt?

Counting only the pure symbol definitions (no module names) with a quick CLI oneliner, I only get 939, so I'm guessing some other parsing then the obvious.

[FineFindus]

Thanks!