message: rpc/listaddressgroupings: redefine inner-most array as ARR_FIXED
  ARR_FIXED is for cases like this, where the elements are in an array for convenience, rather than due to being dynamically sized lists.
diff: @@ -528,7 +528,7 @@ static RPCHelpMan listaddressgroupings()
  {
  {RPCResult::Type::ARR, "", "",
  {
  - {RPCResult::Type::ARR, "", "",
  + {RPCResult::Type::ARR_FIXED, "", "",
  {
  {RPCResult::Type::STR, "address", "The peercoin address"},
  {RPCResult::Type::STR_AMOUNT, "amount", "The amount in " + CURRENCY_UNIT},
  