Move MenuManager functions out of Project.cpp

src/prefs/PrefsDialog.cpp

@@ -553,7 +553,7 @@ void PrefsDialog::OnOK(wxCommandEvent & WXUNUSED(event))
 
    // LL:  wxMac can't handle recreating the menus when this dialog is still active,
    //      so AudacityProject::UpdatePrefs() or any of the routines it calls must
-   //      not cause AudacityProject::RebuildMenuBar() to be executed.
+   //      not cause MenuCreator::RebuildMenuBar() to be executed.
    for (size_t i = 0; i < gAudacityProjects.size(); i++) {
       gAudacityProjects[i]->UpdatePrefs();
    }