Function kebab_to_snake 

pub fn kebab_to_snake(key: &str) -> String

Inverse of the Configurable macro’s internal snake_to_kebab.

Field paths emitted by prop_fields() are kebab-case (per the macro’s snake→kebab transform of the underlying Rust idents). Surfaces that want to display the field under its serde-canonical snake_case spelling — for example api_key rather than api-key — use this to convert.

No-op for keys without -.