Qt: Remove some bogus entries from Authors list

Some lines in Acknowledgements are mistakenly matching the regular
expression to capture authors and email addresses, resulting in
bogus authors entries.

Stop matching authors after we reach the Acknowledgements section.
This matches the structure of the AUTHORS-SHORT file and fixes the
bogus entries.

ui/qt/about_dialog.cpp

@@ -92,7 +92,8 @@ AStringListListModel(parent)
         if (line.contains("Acknowledgements")) {
             readAck = true;
             continue;
-        } else {
+        }
+        else if (!readAck) {
             QRegularExpressionMatch match = rx.match(line);
             if (match.hasMatch())
                 appendRow(QStringList() << match.captured(1).trimmed() << match.captured(2).trimmed());