filesystemmodel: Emit items-changed when modifying attributes
requested to merge ocrete/gtk:gtkfilesystemmodel-emit-items-changed-on-modifying-attributes into main
The filter code in the GtkFileChooserWidget has no other way to know that the content has changed, by emitting the signal, we can tell it up itself.
Fixes #5758 (closed)
Edited by Olivier Crête