Merge pull request #409 from shadeslayer/fix-arb-buffer-storage

Fix ARB_buffer_storage error description
diff --git a/extensions/ARB/ARB_buffer_storage.txt b/extensions/ARB/ARB_buffer_storage.txt
index 5e4e947..0f814f4 100644
--- a/extensions/ARB/ARB_buffer_storage.txt
+++ b/extensions/ARB/ARB_buffer_storage.txt
@@ -409,7 +409,8 @@
     INVALID_OPERATION is generated by MapBufferRange if MAP_PERSISTENT_BIT
     is included in <access> but MAP_PERSISTENT_BIT is not
     included in the buffer's storage flags, or if MAP_COHERENT_BIT is included
-    in <access> but
+    in <access> but MAP_COHERENT_BIT is not
+    included in the buffer's storage flags.
     OUT_OF_MEMORY is generated by BufferStorage and NamedBufferStorageEXT if
     the GL is not able to allocate a data store with the properties requested