doc: Adapt GtkPackType documentation to GTK4 changes

Since GTK4, the functions that used the GtkPackType enumeration,
`gtk_box_pack_{start,end}`, were replaced by `gtk_box_{append,prepend}`,
hence this enumeration isn't used anymore by any function within the
GtkBox type, and the child packing properties were also removed for GTK4.
So this commit adapts the documentation accordingly.

diff --git a/gtk/gtkenums.h b/gtk/gtkenums.h
index 206fdbef12c114068f2a58df0917fa0dc7f56815..d3b6b3e6b236152f482e303468384e577115be6b 100644 (file)
--- a/gtk/gtkenums.h
+++ b/gtk/gtkenums.h
@@ -343,10 +343,11 @@ typedef enum
 
 /**
  * GtkPackType:
- * @GTK_PACK_START: The child is packed into the start of the box
- * @GTK_PACK_END: The child is packed into the end of the box
+ * @GTK_PACK_START: The child is packed into the start of the widget
+ * @GTK_PACK_END: The child is packed into the end of the widget
  *
- * Represents the packing location #GtkBox children
+ * Represents the packing location of a children in its parent.
+ * See #GtkWindowControls for example.
  */
 typedef enum
 {