rpc: Missing doc updates for bumpfee psbt update

Adds updates that have been missed in commit
ea0a7ec:

* RPC help doc update
* Release notes update
* Remove "mutable" keyword from lambda

Author: MarcoFalke

doc/release-notes.md

@@ -110,6 +110,9 @@ Wallet
   The RPC returns public versions of all imported descriptors, including their timestamp and flags.
   For ranged descriptors, it also returns the range boundaries and the next index to generate addresses from. (#20226)
 
+- The `bumpfee` RPC is not available with wallets that have private keys
+  disabled. `psbtbumpfee` can be used instead. (#20891)
+
 GUI changes
 -----------
 

src/wallet/rpcwallet.cpp

@@ -3379,7 +3379,7 @@ RPCHelpMan signrawtransactionwithwallet()
 
 static RPCHelpMan bumpfee_helper(std::string method_name)
 {
-    bool want_psbt = method_name == "psbtbumpfee";
+    const bool want_psbt = method_name == "psbtbumpfee";
     const std::string incremental_fee{CFeeRate(DEFAULT_INCREMENTAL_RELAY_FEE).ToString(FeeEstimateMode::SAT_VB)};
 
     return RPCHelpMan{method_name,
@@ -3413,14 +3413,14 @@ static RPCHelpMan bumpfee_helper(std::string method_name)
                              "still be replaceable in practice, for example if it has unconfirmed ancestors which\n"
                              "are replaceable).\n"},
                     {"estimate_mode", RPCArg::Type::STR, /* default */ "unset", std::string() + "The fee estimate mode, must be one of (case insensitive):\n"
-    "         \"" + FeeModes("\"\n\"") + "\""},
+                             "\"" + FeeModes("\"\n\"") + "\""},
                 },
                 "options"},
         },
         RPCResult{
             RPCResult::Type::OBJ, "", "", Cat(Cat<std::vector<RPCResult>>(
             {
-                {RPCResult::Type::STR, "psbt", "The base64-encoded unsigned PSBT of the new transaction." + std::string(want_psbt ? "" : " Only returned when wallet private keys are disabled. (DEPRECATED)")},
+                {RPCResult::Type::STR, "psbt", "The base64-encoded unsigned PSBT of the new transaction."},
             },
             want_psbt ? std::vector<RPCResult>{} : std::vector<RPCResult>{{RPCResult::Type::STR_HEX, "txid", "The id of the new transaction. Only returned when wallet private keys are enabled."}}
             ),
@@ -3437,7 +3437,7 @@ static RPCHelpMan bumpfee_helper(std::string method_name)
     "\nBump the fee, get the new transaction\'s" + std::string(want_psbt ? "psbt" : "txid") + "\n" +
             HelpExampleCli(method_name, "<txid>")
         },
-        [want_psbt](const RPCHelpMan& self, const JSONRPCRequest& request) mutable -> UniValue
+        [want_psbt](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
     std::shared_ptr<CWallet> const pwallet = GetWalletForJSONRPCRequest(request);
     if (!pwallet) return NullUniValue;