Merge bitcoin#21897: rpc: adjust incorrect RPCHelpMan types

7031721 rpc/listaddressgroupings: redefine inner-most array as ARR_FIXED (Karl-Johan Alm)
8500f7b rpc/createrawtransaction: redefine addresses as OBJ_USER_KEYS (Karl-Johan Alm)
d9e2183 rpc: include OBJ_USER_KEY in RPCArg constructor checks (Karl-Johan Alm)

Pull request description:

  This PR adjusts the two issues I encountered while developing a tool that converts RPCHelpMan objects into bindings for other language(s).

  The first is in createrawtransaction, where the address part, e.g. bc1qabc in

  > createrawtransaction '[]' '[{"bc1qabc": 1.0}]'

  is declared as a `Type::OBJ`, when in reality it should be a `Type::OBJ_USER_KEYS`, defined as such:

  https://github.com/bitcoin/bitcoin/blob/5925f1e652768a9502831b9ccf78d16cf3c37d29/src/rpc/util.h#L126

  (coincidentally, this is the first and only (afaict) usage of this `RPCArg::Type`).

  The second is in the `listaddressgroupings` RPC, which returns an array of arrays of arrays, where the innermost one is a tuple-thingie with an optional 3rd item; this is an `ARR_FIXED`, not an `ARR`.

ACKs for top commit:
  MarcoFalke:
    ACK 7031721 🐀

Tree-SHA512: 769377416c6226d1738a956fb685498e009f9e7eb2d45bc679b81c5364b9520fdbcb49392c937ab45598aa0d33589e8e6a59ccc101cf8d8e7dfdafd58d4eefd0

src/rpc/rawtransaction.cpp

@@ -747,7 +747,7 @@ static RPCHelpMan createrawtransaction()
                     "For compatibility reasons, a dictionary, which holds the key-value pairs directly, is also\n"
                     "                             accepted as second parameter.",
                 {
-                    {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
+                    {"", RPCArg::Type::OBJ_USER_KEYS, RPCArg::Optional::OMITTED, "",
                         {
                             {"address", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "A key-value pair. The key (string) is the Dash address, the value (float or string) is the amount in " + CURRENCY_UNIT},
                         },

src/rpc/util.h

@@ -174,7 +174,7 @@ struct RPCArg {
           m_oneline_description{std::move(oneline_description)},
           m_type_str{std::move(type_str)}
     {
-        CHECK_NONFATAL(type != Type::ARR && type != Type::OBJ);
+        CHECK_NONFATAL(type != Type::ARR && type != Type::OBJ && type != Type::OBJ_USER_KEYS);
     }
 
     RPCArg(
@@ -194,7 +194,7 @@ struct RPCArg {
           m_oneline_description{std::move(oneline_description)},
           m_type_str{std::move(type_str)}
     {
-        CHECK_NONFATAL(type == Type::ARR || type == Type::OBJ);
+        CHECK_NONFATAL(type == Type::ARR || type == Type::OBJ || type == Type::OBJ_USER_KEYS);
     }
 
     bool IsOptional() const;

src/wallet/rpcwallet.cpp

@@ -509,7 +509,7 @@ static RPCHelpMan listaddressgroupings()
             {
                 {RPCResult::Type::ARR, "", "",
                 {
-                    {RPCResult::Type::ARR, "", "",
+                    {RPCResult::Type::ARR_FIXED, "", "",
                     {
                         {RPCResult::Type::STR, "address", "The Dash address"},
                         {RPCResult::Type::STR_AMOUNT, "amount", "The amount in " + CURRENCY_UNIT},