Fix 'approuve' button, add warning when break is not between day start and day end

sources/mainwindow.h

@@ -57,6 +57,7 @@ private:
     void updateEndLabel();
     void highlightDayOfWeek();
     void updateValidIcon();
+    void updateWarningIcon();
 
     QString get_save_file_path();
     Identifier get_identifier(QString objectName);