display doctype 'label' not name in User Messages

here: https://github.com/nuxeo/nuxeo/blob/master/nuxeo-dm/nuxeo-platform-webapp-core/src/main/java/org/nuxeo/ecm/webapp/contentbrowser/DocumentActionsBean.java#L306
and likely in other places in the platform, the User Message displays the Document Type, not its label. This should be changed to display the label, as its there for just such circumstances, and would be more consistent with other screens the User has.