Bump most dev dependencies

[adroitwhiz]

Bumps eslint, prettier, and typescript, along with associated configs. ESLint has a new config format, which I've migrated to.

Newer versions of typescript-eslint and TypeScript seem to have more lints--I've disabled some and manually ignored others.

Prettier v3 is async, so we can't use it in toLeopard. Instead, we continue using v2 there but use v3 for the codebase itself.