[gtk+] Don't mention GdkVisual in the docs

[Matthias Clasen <matthiasc src gnome org>]

commit 61a3a90f89e22cc17b4b7d171cac2f6b4da4b9a9
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Oct 31 22:05:58 2017 -0400

    Don't mention GdkVisual in the docs
    
    It is going away.

 gdk/gdkglcontext.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gdk/gdkglcontext.c b/gdk/gdkglcontext.c
index b8df697..2555423 100644
--- a/gdk/gdkglcontext.c
+++ b/gdk/gdkglcontext.c
@@ -27,8 +27,8 @@
  * OpenGL drawing context.
  *
  * #GdkGLContexts are created for a #GdkWindow using
- * gdk_window_create_gl_context(), and the context will match
- * the #GdkVisual of the window.
+ * gdk_window_create_gl_context(), and the context will match the
+ * the characteristics of the window.
  *
  * A #GdkGLContext is not tied to any particular normal framebuffer.
  * For instance, it cannot draw to the #GdkWindow back buffer. The GDK