Function hookify

pub fn hookify<'a>(
    f: impl FnMut(HookEnv<'_, '_>, &[u8]) -> Vec<Vec<u8>> + Send + Sync + 'a,
) -> BoxedHook<'a>

Wrap a function in a smart pointer so it may be placed in a HookRegistry.

Note: the Send + Sync requirement may be logically extraneous. Requires further investigation.