Adding openapi extension values with derive ToSchema

[jayvdb]

I would like to add x-rust-type to some of my schemas, something like this:

#[derive(..., ToSchema, ...)]
#[schema(x-rust-type = ...)]
pub struct MyId(pub String);

I dont see anything in the docs here to achieve this https://docs.rs/utoipa/latest/utoipa/derive.ToSchema.html

This is to integrate with progenitor , i.e. https://docs.rs/progenitor/latest/progenitor/struct.GenerationSettings.html#method.with_crate