message: Change graph dump instructions
  The flag is --xla_dump_hlo_as_text
diff: @@ -140,8 +140,9 @@ XLA programs and the used auto-clustering embedding.
  To generate them for a TensorFlow program running with auto-clustering, launch:
  ```
  -$ TF_DUMP_GRAPH_PREFIX=/tmp/generated TF_XLA_FLAGS="--tf_xla_clustering_debug
  ---tf_xla_auto_jit=2" XLA_FLAGS="--dump_hlo_as_text --xla_dump_to=/tmp/generated"
  +$ TF_DUMP_GRAPH_PREFIX=/tmp/generated \
  + TF_XLA_FLAGS="--tf_xla_clustering_debug --tf_xla_auto_jit=2" \
  + XLA_FLAGS="--xla_dump_hlo_as_text --xla_dump_to=/tmp/generated" \
  my/tensorflow/program"
  ```
  