[gtk/wip/baedert/for-master] widget: Slightly update opacity docs

[Timm Bäder <baedert src gnome org>]

commit 5d87a1f43fddbbd5f16827eafbaa4ac8a7738613
Author: Timm Bäder <mail baedert org>
Date:   Sun Oct 11 10:17:18 2020 +0200

    widget: Slightly update opacity docs

 gtk/gtkwidget.c | 4 ----
 1 file changed, 4 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 2ea7fb9c3a..37ec32857a 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -1250,8 +1250,6 @@ gtk_widget_class_init (GtkWidgetClass *klass)
    *
    * The requested opacity of the widget. See gtk_widget_set_opacity() for
    * more details about window opacity.
-   *
-   * Before 3.8 this was only available in GtkWindow
    */
   widget_props[PROP_OPACITY] =
       g_param_spec_double ("opacity",
@@ -9647,8 +9645,6 @@ gtk_widget_get_allocated_baseline (GtkWidget *widget)
  * running. See gdk_display_is_composited(). On Windows it should work
  * always, although setting a window’s opacity after the window has been
  * shown causes it to flicker once on Windows.
- *
- * For child widgets it doesn’t work if any affected widget has a native window.
  **/
 void
 gtk_widget_set_opacity (GtkWidget *widget,