message: doc: add coinstatsindex to bitcoin.conf
diff: @@ -134,6 +134,9 @@ rpcport=9902
  # both prior transactions and several dozen future transactions.
  #keypool=100
  +# Maintain coinstats index used by the gettxoutsetinfo RPC (default: 0).
  +#coinstatsindex=1
  +
  # User interface options
  # Start Peercoin minimized
  