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

src/wallet/scriptpubkeyman.cpp

@@ -17,6 +17,7 @@
 
 #include <optional>
 
+namespace wallet {
 //! Value for the first BIP 32 hardened derivation. Can be used as a bit mask and as a value. See BIP 32 for more details.
 const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
 
@@ -2359,3 +2360,4 @@ bool DescriptorScriptPubKeyMan::CanUpdateToWalletDescriptor(const WalletDescript
 
     return true;
 }
+} // namespace wallet