Take Brazilian AS details from NIC.br's WHOIS server (closes #174)

LACNIC's answer for an AS that NIC.br registers is NIC.br's answer with
each accented letter replaced by U+FFFD, so a name such as AS52751's
cannot be recovered from it. When LACNIC's answer carries NIC.br's
copyright notice, the client now also asks whois.registro.br for the AS
and takes the fields from that answer, which is Latin-1 and decoded as
before. When that query fails, when the answer has no fields, or when it
is NIC.br's reduced answer for a client over its query limit, LACNIC's
fields are kept and the lookup still succeeds. The tests use recorded
answers for AS52751.

Model: opus-5-5

TODO.md

@@ -33,6 +33,11 @@ tested.
 
 # Completed Steps
 
+- 2026-10-27: the WHOIS details of a Brazilian AS keep their accented letters.
+  LACNIC's answer for such an AS comes from NIC.br, Brazil's registry, with each
+  accented letter replaced. The details now come from NIC.br's own server,
+  `whois.registro.br`. When that query fails, the details from LACNIC's answer
+  are kept (closes #174)
 - 2026-10-27: `make asupdate` stops with an error when the download of `as.csv`
   breaks off. The generator used to retry the failed read forever. A record that
   does not parse is still logged and skipped (closes #177)