docs: Mark ARB_cull_distance as in progress

Signed-off-by: Tobias Klausmann <tobias.johannes.klausmann@mni.thm.de>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
diff --git a/docs/GL3.txt b/docs/GL3.txt
index 44a824b..8e1c8cd 100644
--- a/docs/GL3.txt
+++ b/docs/GL3.txt
@@ -190,7 +190,7 @@
   GL_ARB_ES3_1_compatibility                           not started
   GL_ARB_clip_control                                  DONE (i965, nv50, nvc0, r600, radeonsi, llvmpipe, softpipe)
   GL_ARB_conditional_render_inverted                   DONE (i965, nv50, nvc0, llvmpipe, softpipe)
-  GL_ARB_cull_distance                                 not started
+  GL_ARB_cull_distance                                 in progress (Tobias)
   GL_ARB_derivative_control                            DONE (i965, nv50, nvc0, r600)
   GL_ARB_direct_state_access                           DONE (all drivers)
   - Transform Feedback object                          DONE