PARTIAL: typofixes (found by misspell_fixer)

Upstream: 9f68ed6b6d1a9c6436ce37913666165f2b180ee3 (PR #6539)

src/qt/paymentserver.cpp

@@ -764,7 +764,7 @@ void PaymentServer::setOptionsModel(OptionsModel *optionsModel)
 
 void PaymentServer::handlePaymentACK(const QString& paymentACKMsg)
 {
-    // currently we don't futher process or store the paymentACK message
+    // currently we don't further process or store the paymentACK message
     Q_EMIT message(tr("Payment acknowledged"), paymentACKMsg, CClientUIInterface::ICON_INFORMATION | CClientUIInterface::MODAL);
 }