message: Update tf_upgrade_v2 docs to add a note about expected 'import tensorflow as
  tf' import and tf2up.ml link.
diff: # TensorFlow Python API Upgrade Utility
  -This tool allows you to upgrade your existing TensorFlow Python scripts.
  -Specifically: \
  -`tf_upgrade_v2.py`: upgrades code from TensorFlow 1.12 to TensorFlow 2.0 preview. \
  -`tf_upgrade.py`: upgrades code to TensorFlow 1.0 from TensorFlow 0.11.
  +This tool allows you to upgrade your existing TensorFlow Python scripts,
  +specifically:
  +* `tf_upgrade_v2.py`: Upgrade code from TensorFlow 1.x to TensorFlow 2.0 preview.
  +* `tf_upgrade.py`: Upgrade code to TensorFlow 1.0 from TensorFlow 0.11.
  ## Running the script from pip package
  @@ -58,17 +58,13 @@ arguments that mismap arguments.
  - This script wouldn't actually reorder arguments. Instead, the script will add
  keyword arguments to functions that had their arguments reordered.
  -- This script is not able to upgrade all functions. One notable example is
  -`tf.nn.conv2d` that no longer takes `use_cudnn_on_gpu` argument.
  -If the script detects this, it will report this to stdout
  -(and in the report), and you can fix it manually. For example if you have
  -`tf.nn.conv2d(inputs, filters, strides, padding, use_cudnn_on_gpu=True)`
  -you will need to manually change it to
  -`tf.nn.conv2d(input, filters, strides, padding)`.
  +- The script assumes that `tensorflow` is imported using `import tensorflow as tf`.
  -- There are some syntaxes that are not handleable with this script as this
  +- Note for upgrading to 2.0: Check out [tf2up.ml](http://tf2up.ml) for a convenient tool to upgrade Jupiter
  + notebooks and Python files in a github repository.
  +
  +- Note for upgrading to 1.0: There are some syntaxes that are not handleable with this script as this
  script was designed to use only standard python packages.
  -There is an alternative available for TensorFlow 0.* to 1.0 upgrade script.
  If the script fails with "A necessary keyword argument failed to be inserted." or
  "Failed to find keyword lexicographically. Fix manually.", you can try
  [@machrisaa's fork of this script](https://github.com/machrisaa/tf0to1).
  