Macro impl_meta_methods 

macro_rules! impl_meta_methods {
    ($ty:ty) => { ... };
}

Getters and fluent setters for every validator’s Meta.

Invoked via impl_meta_methods! on each concrete validator so Integer::new().with_name("Port").to_int() works without importing a trait. Getters read meta(); setters mutate meta_mut() and return self for chaining.