feat(icom): the IC-7760 joins the model list

CI-V default address B2h, per the radio's own menu. Both places that know a
model: the settings dropdown and civ.ModelName.

internal/cat/civ/civ.go

@@ -357,6 +357,8 @@ func ModelName(addr byte) string {
 		return "IC-9700"
 	case 0xA4:
 		return "IC-705"
+	case 0xB2:
+		return "IC-7760"
 	case 0xB6:
 		return "IC-7300MKII"
 	}