wallet: fix doc typo in signer option

Signed-off-by: William Casarin <jb55@jb55.com>

src/wallet/init.cpp

@@ -62,7 +62,7 @@ void WalletInit::AddWalletOptions(ArgsManager& argsman) const
                                                             CURRENCY_UNIT, FormatMoney(CFeeRate{DEFAULT_PAY_TX_FEE}.GetFeePerK())), ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
     argsman.AddArg("-rescan", "Rescan the block chain for missing wallet transactions on startup", ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
 #ifdef ENABLE_EXTERNAL_SIGNER
-    argsman.AddArg("-signer=<cmd>", "External signing tool, see docs/external-signer.md", ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
+    argsman.AddArg("-signer=<cmd>", "External signing tool, see doc/external-signer.md", ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
 #endif
     argsman.AddArg("-spendzeroconfchange", strprintf("Spend unconfirmed change when sending transactions (default: %u)", DEFAULT_SPEND_ZEROCONF_CHANGE), ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
     argsman.AddArg("-txconfirmtarget=<n>", strprintf("If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: %u)", DEFAULT_TX_CONFIRM_TARGET), ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);