Take the Tor exit list from Onionoo, which has the IPv6 exits (closes #234)

check.torproject.org lists IPv4 exits only, so is_tor was false for an IPv6
exit. tor_exits now comes from Onionoo's details document, read by a new
format that takes every address in exit_addresses and or_addresses.

Model: opus-5-5

internal/iplist/parse.go

@@ -164,17 +164,6 @@ func addDShieldNetwork(builder *netipx.IPSetBuilder, line string) error {
 	return nil
 }
 
-// onionooDetails is the part of an Onionoo details document that holds the
-// relays' addresses.
-//
-//nolint:tagliatelle // Onionoo's own field names
-type onionooDetails struct {
-	Relays []struct {
-		ExitAddresses []string `json:"exit_addresses"`
-		ORAddresses   []string `json:"or_addresses"`
-	} `json:"relays"`
-}
-
 // parseOnionoo returns every address in the exit_addresses and or_addresses
 // fields of the relays in an Onionoo details document. A document with no
 // addresses fails, because the Tor network always has relays.
@@ -184,7 +173,13 @@ func parseOnionoo(r io.Reader) (*netipx.IPSet, error) {
 		return nil, err
 	}
 
-	var details onionooDetails
+	//nolint:tagliatelle // Onionoo's own field names
+	var details struct {
+		Relays []struct {
+			ExitAddresses []string `json:"exit_addresses"`
+			ORAddresses   []string `json:"or_addresses"`
+		} `json:"relays"`
+	}
 
 	err = json.Unmarshal(data, &details)
 	if err != nil {