Some admin pages are missing breadcrumbs

This is an issue for the shortcuts and taxonomy sub pages at the very least. It arises for dynamic menu items, that are not being added as menu links in the management tree. Examples include the page for configuring a taxonomy vocabulary. Or for configuring the links for a shortcut set.

The problem is sorted on the configuration pages for the menu module by manually adding e.g. admin/structure/menu/manage/menu-my-new-menu using menu_link_save(). Perhaps we should do that elsewhere.