Fix documentation.

* doc/chapters/advances-examples.texi: fix wrong reference to `starpu_filter'
  by `starpu_data_filter'.

doc/chapters/advanced-examples.texi

@@ -232,7 +232,7 @@ starpu_vector_data_register(&handle, 0, (uintptr_t)vector,
                             NX, sizeof(vector[0]));
 
 /* Partition the vector in PARTS sub-vectors */
-starpu_filter f =
+starpu_data_filter f =
 @{
     .filter_func = starpu_block_filter_func_vector,
     .nchildren = PARTS