GUI: Enable information messages.

Dan added new enable-flag for information messages in commit 033e759.
Enable that flag for GUI so that the information messages are visible
in the GUI.

gui/mainwindow.cpp

@@ -391,6 +391,7 @@ Settings MainWindow::GetCppcheckSettings()
     }
 
     result.addEnabled("style");
+    result.addEnabled("information");
     result.debug = false;
     result.debugwarnings = mSettings->value(SETTINGS_SHOW_DEBUG_WARNINGS, false).toBool();
     result._errorsOnly = false;