[gimp] app: add eye icon to the GimpItemTreeView header's visibility column.

[Jehan <jehanp src gnome org>]

commit 7607261d68d6f7a9bd0196c71a08773c7abb5205
Author: Jehan <jehan girinstud io>
Date:   Thu Dec 23 18:40:17 2021 +0100

    app: add eye icon to the GimpItemTreeView header's visibility column.
    
    Makes it much more obvious where you have to click for visibility, and
    where each column is. Also it's more consistent.

 app/widgets/gimpitemtreeview.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/app/widgets/gimpitemtreeview.c b/app/widgets/gimpitemtreeview.c
index 55a1cdabdb..9affca8a8f 100644
--- a/app/widgets/gimpitemtreeview.c
+++ b/app/widgets/gimpitemtreeview.c
@@ -373,7 +373,7 @@ gimp_item_tree_view_constructed (GObject *object)
   GimpContainerTreeView *tree_view       = GIMP_CONTAINER_TREE_VIEW (object);
   GimpItemTreeView      *item_view       = GIMP_ITEM_TREE_VIEW (object);
   GtkTreeViewColumn     *column;
-  GtkWidget             *lock_image;
+  GtkWidget             *image;
   GtkIconSize            button_icon_size;
   gint                   button_spacing;
 
@@ -399,6 +399,9 @@ gimp_item_tree_view_constructed (GObject *object)
                     item_view);
 
   column = gtk_tree_view_column_new ();
+  image = gtk_image_new_from_icon_name (GIMP_ICON_VISIBLE, button_icon_size);
+  gtk_tree_view_column_set_widget (column, image);
+  gtk_widget_show (image);
   gtk_tree_view_insert_column (tree_view->view, column, 0);
 
   item_view->priv->eye_cell = gimp_cell_renderer_toggle_new (GIMP_ICON_VISIBLE);
@@ -425,9 +428,9 @@ gimp_item_tree_view_constructed (GObject *object)
                     item_view);
 
   column = gtk_tree_view_column_new ();
-  lock_image = gtk_image_new_from_icon_name (GIMP_ICON_LOCK, button_icon_size);
-  gtk_tree_view_column_set_widget (column, lock_image);
-  gtk_widget_show (lock_image);
+  image = gtk_image_new_from_icon_name (GIMP_ICON_LOCK, button_icon_size);
+  gtk_tree_view_column_set_widget (column, image);
+  gtk_widget_show (image);
   gtk_tree_view_insert_column (tree_view->view, column, 1);
 
   item_view->priv->lock_cell = gimp_cell_renderer_toggle_new (GIMP_ICON_LOCK_MULTI);