[retro-gtk/build-doc: 9/11] gl-display: Give it some private section documentation

[Adrien Plazas <aplazas src gnome org>]

commit a2ebdff0132ce2fa1ddc19d547d901cd136ce1f7
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Fri Apr 17 15:45:14 2020 +0200

    gl-display: Give it some private section documentation

 retro-gtk/retro-gl-display.c | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/retro-gtk/retro-gl-display.c b/retro-gtk/retro-gl-display.c
index a6a3a0f..0c07765 100644
--- a/retro-gtk/retro-gl-display.c
+++ b/retro-gtk/retro-gl-display.c
@@ -1,5 +1,13 @@
 // This file is part of retro-gtk. License: GPL-3.0+.
 
+/**
+ * PRIVATE:retro-gl-display
+ * @short_description: A widget rendering the video output from a core via OpenGL
+ * @title: RetroGLDisplay
+ * @See_also: #RetroCairoDisplay
+ * @stability: Private
+ */
+
 #include "retro-gl-display-private.h"
 
 #include <epoxy/gl.h>