In the `script` module remove the wildcards and re-export stuff from
`self` explicitly in both `primitives` and `bitcoin`.
Internal change only, everything is re-exported.
Currently we feature gate code within the `impl_to_hex_from_lower_hex`
macro on "alloc" but `bitcoin` does not have the "alloc" feature so
this code is never built in. This can be seen by the lack of a
`to_hex` function on `LeafVersion`.
Remove the feature gate from the macro and put it on the individual
call sites as needed.
Tobin C. Harding