Clarify in sendmany/z_sendmany rpc docs that amounts are not floating point

src/wallet/rpcwallet.cpp

@@ -960,7 +960,7 @@ UniValue sendmany(const UniValue& params, bool fHelp)
     if (fHelp || params.size() < 2 || params.size() > 5)
         throw runtime_error(
             "sendmany \"fromaccount\" {\"address\":amount,...} ( minconf \"comment\" [\"address\",...] )\n"
-            "\nSend multiple times. Amounts are double-precision floating point numbers."
+            "\nSend multiple times. Amounts are decimal numbers with at most 8 digits of precision."
             + HelpRequiringPassphrase() + "\n"
             "\nArguments:\n"
             "1. \"fromaccount\"         (string, required) MUST be set to the empty string \"\" to represent the default account. Passing any other string will result in an error.\n"
@@ -3583,7 +3583,7 @@ UniValue z_sendmany(const UniValue& params, bool fHelp)
     if (fHelp || params.size() < 2 || params.size() > 4)
         throw runtime_error(
             "z_sendmany \"fromaddress\" [{\"address\":... ,\"amount\":...},...] ( minconf ) ( fee )\n"
-            "\nSend multiple times. Amounts are double-precision floating point numbers."
+            "\nSend multiple times. Amounts are decimal numbers with at most 8 digits of precision."
             "\nChange generated from a taddr flows to a new taddr address, while change generated from a zaddr returns to itself."
             "\nWhen sending coinbase UTXOs to a zaddr, change is not allowed. The entire value of the UTXO(s) must be consumed."
             + strprintf("\nBefore Sapling activates, the maximum number of zaddr outputs is %d due to transaction size limits.\n", Z_SENDMANY_MAX_ZADDR_OUTPUTS_BEFORE_SAPLING)