[gtk/matthiasc/for-master: 50/56] TreeView: add missing nullability annotations

[Matthias Clasen <matthiasc src gnome org>]

commit 50310f7b148f555265f916c1064dd5d7836c2fdc
Author: Bilal Elmoussaoui <bil elmoussaoui gmail com>
Date:   Tue Nov 24 17:57:32 2020 +0100

    TreeView: add missing nullability annotations

 gtk/gtktreeview.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtktreeview.c b/gtk/gtktreeview.c
index f404eec9e4..def80e5776 100644
--- a/gtk/gtktreeview.c
+++ b/gtk/gtktreeview.c
@@ -11067,10 +11067,11 @@ gtk_tree_view_set_expander_column (GtkTreeView       *tree_view,
  * gtk_tree_view_get_expander_column:
  * @tree_view: A #GtkTreeView
  *
- * Returns the column that is the current expander column.
+ * Returns the column that is the current expander column,
+ * or %NULL if none has been set.
  * This column has the expander arrow drawn next to it.
  *
- * Returns: (transfer none): The expander column.
+ * Returns: (transfer none) (nullable): The expander column.
  **/
 GtkTreeViewColumn *
 gtk_tree_view_get_expander_column (GtkTreeView *tree_view)
@@ -13178,7 +13179,7 @@ gtk_treeview_snapshot_border (GtkSnapshot           *snapshot,
  * Creates a #cairo_surface_t representation of the row at @path.  
  * This image is used for a drag icon.
  *
- * Returns: (transfer full): a newly-allocated surface of the drag icon.
+ * Returns: (transfer full) (nullable): a newly-allocated surface of the drag icon.
  **/
 GdkPaintable *
 gtk_tree_view_create_row_drag_icon (GtkTreeView  *tree_view,
@@ -13481,7 +13482,7 @@ gtk_tree_view_set_search_equal_func (GtkTreeView                *tree_view,
  * entry for @tree_view.  In case the built-in entry is being used, %NULL
  * will be returned.
  *
- * Returns: (transfer none): the entry currently in use as search entry.
+ * Returns: (transfer none) (nullable): the entry currently in use as search entry.
  */
 GtkEditable *
 gtk_tree_view_get_search_entry (GtkTreeView *tree_view)