Adding a record type used to require 5 edits across the file (enum
variant, to_num, from_num, as_str, parse_str). The macro takes a
single (variant, num, str) tuple per type and generates the enum
plus all four methods.
UNKNOWN(u16) stays hand-coded since it carries data and can't sit
in the table.
src/question.rs: 156 lines -> 92 lines, no behavior change.
Logs were printing UNKNOWN(64), UNKNOWN(29), UNKNOWN(35) for SVCB,
LOC, and NAPTR — three RR types that have been registered for years
and show up in the wild (notably SVCB via RFC 9462 DDR clients
querying _dns.resolver.arpa).
Adds the variants and replaces the SVCB_QTYPE u16 const introduced
in #119 with QueryType::SVCB.to_num(), matching the HTTPS path.
Closes#114.
