Closes #486.

The previous message read "Hostname X is resolved to Y addresses, not
Z" with Z being either the detected IPv4 or IPv6 (whichever was set
first), which made dual-stack mismatches confusing — a hostname
resolving to v6 only on a host with v4 detected and v6 undetected
printed "not <v4>" without hinting that v6 was the missing piece.

The reworked template lists the resolved DNS records and both public
addresses (or "<not detected>" when missing) so the gap is obvious:

    Hostname X resolves to "<v6>", but the proxy's public IP is
    1.2.3.4 (IPv4) / <not detected> (IPv6) — none of the resolved
    addresses match

Pure message change.