rpc: fix/add missing RPCExamples for "Util" RPCs

fixes HelpExampleRpc for
    - createmultisig

adds missing HelpExampleRpc for
    - deriveaddresses
    - estimatesmartfee
    - getdescriptorinfo

src/rpc/mining.cpp

@@ -1030,7 +1030,8 @@ static UniValue estimatesmartfee(const JSONRPCRequest& request)
             "have been observed to make an estimate for any number of blocks."},
                     }},
                 RPCExamples{
-                    HelpExampleCli("estimatesmartfee", "6")
+                    HelpExampleCli("estimatesmartfee", "6") +
+                    HelpExampleRpc("estimatesmartfee", "6")
                 },
             }.Check(request);
 

src/rpc/misc.cpp

@@ -98,7 +98,7 @@ static RPCHelpMan createmultisig()
             "\nCreate a multisig address from 2 public keys\n"
             + HelpExampleCli("createmultisig", "2 \"[\\\"03789ed0bb717d88f7d321a368d905e7430207ebbd82bd342cf11ae157a7ace5fd\\\",\\\"03dbc6764b8884a92e871274b87583e6d5c2a58819473e17e107ef3f6aa5a61626\\\"]\"") +
             "\nAs a JSON-RPC call\n"
-            + HelpExampleRpc("createmultisig", "2, \"[\\\"03789ed0bb717d88f7d321a368d905e7430207ebbd82bd342cf11ae157a7ace5fd\\\",\\\"03dbc6764b8884a92e871274b87583e6d5c2a58819473e17e107ef3f6aa5a61626\\\"]\"")
+            + HelpExampleRpc("createmultisig", "2, [\"03789ed0bb717d88f7d321a368d905e7430207ebbd82bd342cf11ae157a7ace5fd\",\"03dbc6764b8884a92e871274b87583e6d5c2a58819473e17e107ef3f6aa5a61626\"]")
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
@@ -143,6 +143,8 @@ static RPCHelpMan createmultisig()
 
 static RPCHelpMan getdescriptorinfo()
 {
+    const std::string EXAMPLE_DESCRIPTOR = "wpkh([d34db33f/84h/0h/0h]0279be667ef9dcbbac55a06295Ce870b07029Bfcdb2dce28d959f2815b16f81798)";
+
     return RPCHelpMan{"getdescriptorinfo",
             {"\nAnalyses a descriptor.\n"},
             {
@@ -160,7 +162,8 @@ static RPCHelpMan getdescriptorinfo()
             },
             RPCExamples{
                 "Analyse a descriptor\n" +
-                HelpExampleCli("getdescriptorinfo", "\"wpkh([d34db33f/84h/0h/0h]0279be667ef9dcbbac55a06295Ce870b07029Bfcdb2dce28d959f2815b16f81798)\"")
+                HelpExampleCli("getdescriptorinfo", "\"" + EXAMPLE_DESCRIPTOR + "\"") +
+                HelpExampleRpc("getdescriptorinfo", "\"" + EXAMPLE_DESCRIPTOR + "\"")
             },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
@@ -186,6 +189,8 @@ static RPCHelpMan getdescriptorinfo()
 
 static RPCHelpMan deriveaddresses()
 {
+    const std::string EXAMPLE_DESCRIPTOR = "wpkh([d34db33f/84h/0h/0h]xpub6DJ2dNUysrn5Vt36jH2KLBT2i1auw1tTSSomg8PhqNiUtx8QX2SvC9nrHu81fT41fvDUnhMjEzQgXnQjKEu3oaqMSzhSrHMxyyoEAmUHQbY/0/*)#cjjspncu";
+
     return RPCHelpMan{"deriveaddresses",
             {"\nDerives one or more addresses corresponding to an output descriptor.\n"
             "Examples of output descriptors are:\n"
@@ -208,7 +213,8 @@ static RPCHelpMan deriveaddresses()
             },
             RPCExamples{
                 "First three native segwit receive addresses\n" +
-                HelpExampleCli("deriveaddresses", "\"wpkh([d34db33f/84h/0h/0h]xpub6DJ2dNUysrn5Vt36jH2KLBT2i1auw1tTSSomg8PhqNiUtx8QX2SvC9nrHu81fT41fvDUnhMjEzQgXnQjKEu3oaqMSzhSrHMxyyoEAmUHQbY/0/*)#cjjspncu\" \"[0,2]\"")
+                HelpExampleCli("deriveaddresses", "\"" + EXAMPLE_DESCRIPTOR + "\" \"[0,2]\"") +
+                HelpExampleRpc("deriveaddresses", "\"" + EXAMPLE_DESCRIPTOR + "\", \"[0,2]\"")
             },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {