addItem
Adds a new resource, pointed by @uri, into the recently used resources list.
This function automatically retrieves some of the needed metadata and setting other metadata to common default values; it then feeds the data to method@Gtk.RecentManager.add_full.
See method@Gtk.RecentManager.add_full if you want to explicitly define the metadata for the resource pointed by @uri.
Return
true if the new item was successfully added to the recently used resources list
Parameters
uri
a valid URI