Include os version 'windows-10.0.19042' in about dialog

src/libsync/theme.cpp

@@ -468,6 +468,8 @@ QString Theme::about() const
 
     devString += tr("<p><small>Using virtual files plugin: %1</small></p>")
                      .arg(Vfs::modeToString(bestAvailableVfsMode()));
+    devString += tr("<br>%1")
+              .arg(QSysInfo::productType() % QLatin1Char('-') % QSysInfo::kernelVersion());
 
     return devString;
 }