Merge bitcoin#12702: [wallet] [rpc] [doc] importprivkey: hint about i…

…mportmulti

4e05687 [wallet] [rpc] [doc] importprivkey: hint about importmulti (Karl-Johan Alm)

Pull request description:

  From bitcoin#12701, a hint about `importmulti` inside the help for `importprivkey` seems useful.

Tree-SHA512: 09ddfd384062b4365f678167076cb9f5af1eb8f083714a20c2a9bb14fef1c886d1666196272bf09862537166d15ae89c3330cdc6836eee76cb54d137e53301df

src/wallet/rpcdump.cpp

@@ -81,6 +81,7 @@ UniValue importprivkey(const JSONRPCRequest& request)
         throw std::runtime_error(
             "importprivkey \"privkey\" ( \"label\" ) ( rescan )\n"
             "\nAdds a private key (as returned by dumpprivkey) to your wallet. Requires a new wallet backup.\n"
+            "Hint: use importmulti to import more than one private key.\n"
             "\nArguments:\n"
             "1. \"privkey\"          (string, required) The private key (see dumpprivkey)\n"
             "2. \"label\"            (string, optional, default=\"\") An optional label\n"