feat!: project overhaul

[antfu]

I am sorry I basically rewrote this repo 🙈

fix #30

Notable changes:

• Removed the build setup for extension scripts - since we are just a grammar extension and does not need any JS. This also gets rid of Webpack and the toolchain
• Migrate to pnpm
• Use Nuxt's eslint config
• Move the grammar to TS, so we could have type and multiline strings, etc.
• Fix a few minor details of the grammar. A quick comparison:

[Atinux]

Thank you!