Function resolve_globals 

pub fn resolve_globals<K, H: Clone>(
    handlers: &mut HashMap<K, Vec<H>>,
    global_handlers: &[H],
    key: impl Fn(&H) -> u8,
)

Clone the global handlers into every key list and sort each list by priority.

After resolving, the handler set should be considered frozen; mutating it afterwards would break the ordering or the global-handler copies.