Add src/wallet/* code to wallet:: namespace

src/wallet/wallet.cpp

@@ -48,6 +48,7 @@
 
 using interfaces::FoundBlock;
 
+namespace wallet {
 const std::map<uint64_t,std::string> WALLET_FLAG_CAVEATS{
     {WALLET_FLAG_AVOID_REUSE,
         "You need to rescan the blockchain in order to correctly mark used "
@@ -3433,3 +3434,4 @@ ScriptPubKeyMan* CWallet::AddWalletDescriptor(WalletDescriptor& desc, const Flat
 
     return spk_man;
 }
+} // namespace wallet