use qualified paths for all macro generated signatures

[chaoky]

I stumbled upon this when defining my Api's result type,
not prefixing the module's name is a Rust convention ie. module::Result instead of module::ModuleResult.

is there a reason to not use qualified paths in the generated code?

type Result<T> = std::result::Result<T, Error>;

#[tarpc::service]
pub trait Api {
    async fn active_tables() -> Result<Vec<Instance>>;
    async fn all_tables(from: usize, to: usize) -> Result<Vec<Instance>>;
    async fn update_table(new_table: Instance) -> Result<()>;
}

#[derive(Error, Debug, Serialize, Deserialize)]
pub enum Error {
    ...
}

[tikue]

Hi, sorry for not responding last year! There was no reason other than laziness! And as of #417, it should be fixed :)