Function cruncher

pub const fn cruncher<const A: usize>(
    opts: &[Option<&'static NamedType>],
) -> [&'static NamedType; A]

This function reduces a &[Option<&NamedType>] to a [&NamedType; A].

The parameter A should be calculated by type_chewer_nty().

We also validate that all items >= idx A are in fact None.