doc: Add -rpcclienttimeout=0 to loadtxoutset examples

doc/assumeutxo.md

@@ -17,7 +17,7 @@ Once you've obtained the snapshot, you can use the RPC command `loadtxoutset` to
 load it.
 
 ```
-$ bitcoin-cli loadtxoutset /path/to/input
+$ bitcoin-cli -rpcclienttimeout=0 loadtxoutset /path/to/input
 ```
 
 After the snapshot has loaded, the syncing process of both the snapshot chain

src/rpc/blockchain.cpp

@@ -3005,7 +3005,7 @@ static RPCHelpMan loadtxoutset()
                 }
         },
         RPCExamples{
-            HelpExampleCli("loadtxoutset", "utxo.dat")
+            HelpExampleCli("loadtxoutset -rpcclienttimeout=0", "utxo.dat")
         },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {