Summary

This PR adds __ prefix to the generated partial records and variants generated from #[CgpData].

This is to emphasize that the partial data types generated are meant for internal use by CGP, and that the users should not refer to the concrete types directly.

Example

Given the following:

#[derive(CgpData)]
pub struct Person {
    pub name: String,
    pub age: u8,
}

The partial records that is generated would be named as __PartialPerson instead of PartialPerson:

pub struct __PartialPerson<F0: MapType, F1: MapType> {
    pub name: F0::Map<String>,
    pub age: F1::Map<u8>,
}