ProjectDocument: add warning

GUI/Model/Project/ProjectDocument.cpp

@@ -273,6 +273,8 @@ void ProjectDocument::onModelChanged()
 
 void ProjectDocument::writeProject(QIODevice* device, const QString& projectDir)
 {
+    // NOTE: The ordering of the XML elements is important in initialization
+
     QXmlStreamWriter w(device);
     w.setAutoFormatting(true);
     w.writeStartDocument();