Add support for functions

[caleidon]

It would be cool if just like with types and structs, we could also add a prefix before a function, and we'd get full TS support for that rust function. This would be very useful when working with things like Tauri, because we use "Invoke("functionName")" which is very error prone and you don't really get intellisense autocompletion.

Something like this could be auto-generated:
https://github.com/tauri-apps/tauri-plugin-store/blob/dev/webview-src/index.ts

[itsezc]

Would also be very useful for wasm_bindgen when exporting

[escritorio-gustavo]

Can you show us what you'd like this to look like?

[escritorio-gustavo]

I'm currently working on a way to export function signatures as types, check out #249.

For the case of Tauri commands, I don't think we can export the invoke command itself, only the signature, the idea is that you'd then create a function with the exported signature that uses invoke inside it, then you'd call that function instead of invoke