[cogl] attribute-buffer: add missing annotation

[Robert Bragg <rbragg src gnome org>]

commit a53a855507b359b9e9aab1d9640b2ab0268d7a89
Author: Lionel Landwerlin <llandwerlin gmail com>
Date:   Thu Sep 5 11:53:18 2013 +0100

    attribute-buffer: add missing annotation
    
    Reviewed-by: Robert Bragg <robert linux intel com>
    
    (cherry picked from commit 8dc74800023b63af4be1aa45cd8ff77af5fc7f2e)

 cogl/cogl-attribute-buffer.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/cogl/cogl-attribute-buffer.h b/cogl/cogl-attribute-buffer.h
index 29181c1..caa4c5e 100644
--- a/cogl/cogl-attribute-buffer.h
+++ b/cogl/cogl-attribute-buffer.h
@@ -81,7 +81,8 @@ cogl_attribute_buffer_new_with_size (CoglContext *context,
  * cogl_attribute_buffer_new:
  * @context: A #CoglContext
  * @bytes: The number of bytes to allocate for vertex attribute data.
- * @data: An optional pointer to vertex data to upload immediately.
+ * @data: (array length=bytes): An optional pointer to vertex data to
+ *        upload immediately.
  *
  * Describes a new #CoglAttributeBuffer of @size bytes to contain
  * arrays of vertex attribute data and also uploads @size bytes read