Update POTFILES.in
- Found that
gimpcontainertreeview.c
was missing from POTFILES.in when trying to figure out why the "%d items selected" text when selecting multiple layers wasn't translated. - Also add
gimpdrawable-filters.c
that had some translatable strings.
https://l10n.gnome.org/module/gimp/ sees that the latter was missing, but misses the former, possibly since that uses ngettext().