[gtk] stack: Fix some documentation mishaps

[Timm Bäder <baedert src gnome org>]

commit 652323a4bfc4ab78062844bafc15e4a90b16047e
Author: Timm Bäder <mail baedert org>
Date:   Mon Jun 15 10:30:40 2020 +0200

    stack: Fix some documentation mishaps

 gtk/gtkstack.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkstack.c b/gtk/gtkstack.c
index a46e897ca0..348ada48c5 100644
--- a/gtk/gtkstack.c
+++ b/gtk/gtkstack.c
@@ -2477,9 +2477,9 @@ gtk_stack_init (GtkStack *stack)
  * @stack: a #GtkStack
  *
  * Returns a #GListModel that contains the pages of the stack,
- * and can be used to keep and up-to-date view. The model also
+ * and can be used to keep an up-to-date view. The model also
  * implements #GtkSelectionModel and can be used to track and
- * modify the visible page..
+ * modify the visible page.
  *
  * Returns: (transfer full): a #GtkSelectionModel for the stack's children
  */