Fix comment typos in scriptpubkeyman.cpp, wallet.cpp, wallet.h

Fix comment typos:
sigature -> signature
ponter -> pointer
it's key -> its key

src/wallet/scriptpubkeyman.cpp

@@ -586,7 +586,7 @@ bool LegacyScriptPubKeyMan::CanProvide(const CScript& script, SignatureData& sig
         // or solving information, even if not able to sign fully.
         return true;
     } else {
-        // If, given the stuff in sigdata, we could make a valid sigature, then we can provide for this script
+        // If, given the stuff in sigdata, we could make a valid signature, then we can provide for this script
         ProduceSignature(*this, DUMMY_SIGNATURE_CREATOR, script, sigdata);
         if (!sigdata.signatures.empty()) {
             // If we could make signatures, make sure we have a private key to actually make a signature

src/wallet/wallet.cpp

@@ -124,7 +124,7 @@ bool RemoveWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet
     interfaces::Chain& chain = wallet->chain();
     std::string name = wallet->GetName();
 
-    // Unregister with the validation interface which also drops shared ponters.
+    // Unregister with the validation interface which also drops shared pointers.
     wallet->m_chain_notifications_handler.reset();
     LOCK(context.wallets_mutex);
     std::vector<std::shared_ptr<CWallet>>::iterator i = std::find(context.wallets.begin(), context.wallets.end(), wallet);

src/wallet/wallet.h

@@ -195,7 +195,7 @@ public:
     util::Result<CTxDestination> GetReservedDestination(bool internal);
     //! Return reserved address
     void ReturnDestination();
-    //! Keep the address. Do not return it's key to the keypool when this object goes out of scope
+    //! Keep the address. Do not return its key to the keypool when this object goes out of scope
     void KeepDestination();
 };