rpc: Note in fundrawtransaction doc, fee rate is for package

Author: benthecarman

src/wallet/rpc/spend.cpp

@@ -757,7 +757,10 @@ RPCHelpMan fundrawtransaction()
                 "Note that all inputs selected must be of standard form and P2SH scripts must be\n"
                 "in the wallet using importdescriptors (to calculate fees).\n"
                 "You can see whether this is the case by checking the \"solvable\" field in the listunspent output.\n"
-                "Only pay-to-pubkey, multisig, and P2SH versions thereof are currently supported for watch-only\n",
+                "Only pay-to-pubkey, multisig, and P2SH versions thereof are currently supported for watch-only.\n"
+                "Note that if specifying an exact fee rate, the resulting transaction may have a higher fee rate\n"
+                "if the transaction has unconfirmed inputs. This is because the wallet will attempt to make the\n"
+                "entire package have the given fee rate, not the resulting transaction.\n",
                 {
                     {"hexstring", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The hex string of the raw transaction"},
                     {"options", RPCArg::Type::OBJ_NAMED_PARAMS, RPCArg::Optional::OMITTED, "For backward compatibility: passing in a true instead of an object will result in {\"includeWatching\":true}",