[cogl] onscreen: add constructor annotation

[Robert Bragg <rbragg src gnome org>]

commit a514faf8e2ef8a36c22cb72481d7f23d3b9f4b74
Author: Lionel Landwerlin <llandwerlin gmail com>
Date:   Tue Sep 3 22:01:50 2013 +0100

    onscreen: add constructor annotation
    
    Reviewed-by: Robert Bragg <robert linux intel com>
    
    (cherry picked from commit 6ed5a43b8206165cca198330063c322b1e62465e)

 cogl/cogl-onscreen.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/cogl/cogl-onscreen.h b/cogl/cogl-onscreen.h
index a28559c..6c707bf 100644
--- a/cogl/cogl-onscreen.h
+++ b/cogl/cogl-onscreen.h
@@ -43,7 +43,7 @@ typedef struct _CoglOnscreen CoglOnscreen;
 #define COGL_ONSCREEN(X) ((CoglOnscreen *)(X))
 
 /**
- * cogl_onscreen_new:
+ * cogl_onscreen_new: (constructor)
  * @context: A #CoglContext
  * @width: The desired framebuffer width
  * @height: The desired framebuffer height