Macro kompact_config 

macro_rules! kompact_config {
    ($name:ident,
    key = $key:literal,
    type = $value_type:ty,
    default = $default:expr,
    validate = |$value_id:ident| $validate:expr,
    doc = $doc:literal,
    version = $version:literal) => { ... };
    ($name:ident,
    key = $key:literal,
    type = $value_type:ty,
    default = $default:expr,
    doc = $doc:literal,
    version = $version:literal) => { ... };
    ($name:ident,
    key = $key:literal,
    type = $value_type:ty,
    doc = $doc:literal,
    version = $version:literal) => { ... };
    ($name:ident,
    key = $key:literal,
    doc = $doc:literal,
    version = $version:literal) => { ... };
}

Macro to create config entries.

This macro also generated rustdoc that is consistent with the key and the doc field.