popover: Add missing nullable annotation

Fixes https://gitlab.gnome.org/GNOME/gtk/-/issues/4556.

Looks like the other `Popover` methods are have correct nullable
annotations.

diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index 2ef05001713ab60c3373d2dd2d3b2495a606175c..3c16e8931214973ecbf324184e90f987fe98ec65 100644 (file)
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -2103,7 +2103,7 @@ gtk_popover_buildable_init (GtkBuildableIface *iface)
 /**
  * gtk_popover_set_pointing_to: (attributes org.gtk.Method.set_property=pointing-to)
  * @popover: a `GtkPopover`
- * @rect: rectangle to point to
+ * @rect: (nullable): rectangle to point to
  *
  * Sets the rectangle that @popover points to.
  *