Function numeric_input 

pub fn numeric_input(
    value: &str,
    selection: &Selection,
    key: &str,
    opts: NumericInputOpts<'_>,
) -> El

A numeric input field. Defaults to the flanked layout [−] [text_input] [+]; opt into the stacked-chevron variant with NumericInputOpts::stacked.

The two spinner buttons are routed {key}:dec and {key}:inc in both layouts; the inner text input is keyed {key}:field. The wrapping row is keyed {key} itself so layout/test code can find the whole composite by the same name the app uses.