30bb93c676 Implement impl_to_hex_from_lower_hex macro for types that implement fmt::LowerHex (Shing Him Ng)
Pull request description:
Created a macro that implements `to_hex` for types that currently have `core::fmt::LowerHex` and called it on types that have `core::fmt::LowerHex` implemented. I put the macro in the `internals` crate since there are types across the whole project that can potentially use this.
Resolves#2869
ACKs for top commit:
Kixunil:
ACK 30bb93c676
apoelstra:
ACK 30bb93c676 successfully ran local tests
Tree-SHA512: d3ebc7b5c0c23f1a8f8eef4379c1b475e8c23845e18ce514cb1e98eb63fc4f215e6bc4425f97c7303053df13374ef931ae9d9373badd7ca1975a55b0d00d0e40