[gtk] Revert "Update comment annotations of gtk_tree_model_iter_previous and gtk_tree_model_iter_next to s

[Christoph Reiter <creiter src gnome org>]

commit 65d57877a8aa2ef28a36a14c1c73692bf37c0a78
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Sun Nov 15 13:36:35 2020 +0100

    Revert "Update comment annotations of gtk_tree_model_iter_previous and gtk_tree_model_iter_next to state 
that the ITER parameter is modified."
    
    This reverts commit 1340ff2bc279329dc16b8d823100fec46b2f11d8.
    
    Same as with 53cd499621b5

 gtk/gtktreemodel.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtktreemodel.c b/gtk/gtktreemodel.c
index b4ae17545e..377a365d7b 100644
--- a/gtk/gtktreemodel.c
+++ b/gtk/gtktreemodel.c
@@ -1426,7 +1426,7 @@ gtk_tree_model_get_value (GtkTreeModel *tree_model,
 /**
  * gtk_tree_model_iter_next:
  * @tree_model: a #GtkTreeModel
- * @iter: (inout): the #GtkTreeIter-struct
+ * @iter: (in): the #GtkTreeIter-struct
  *
  * Sets @iter to point to the node following it at the current level.
  *
@@ -1474,7 +1474,7 @@ gtk_tree_model_iter_previous_default (GtkTreeModel *tree_model,
 /**
  * gtk_tree_model_iter_previous:
  * @tree_model: a #GtkTreeModel
- * @iter: (inout): the #GtkTreeIter-struct
+ * @iter: (in): the #GtkTreeIter-struct
  *
  * Sets @iter to point to the previous node at the current level.
  *