* Convert impl_key_prefix_for to proc macro * Reduce the number of let bindings * Remove parsing of inputs for impl_key_prefix_for_tuples * Replace unwrap with expect * Remove unnecessary array of idents * Use numeric identifiers * Simplify ident generation * Fix whitespacing * Add documentation for impl_key_prefix_for_tuple proc macro Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com> Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>