message: Replace link to the Python HOW-TO with a link to the Tink documentation site.
  The PyPI package page (https://pypi.org/project/tink/) uses this
  README.md file as the project description. Since this link uses a
  relative path, it's broken when rendered on that site.
diff: @@ -15,8 +15,7 @@ Google Assistant, Firebase, the Android Search App, etc.
  ## Documentation
  -For an overview of using Tink in Python, see the
  -[Python HOW-TO](../docs/PYTHON-HOWTO.md).
  +For an overview of using Tink in Python, see https://developers.google.com/tink.
  In addition, there are illustrative [examples of using Tink
  Python](https://github.com/google/tink/tree/master/examples/python/) which can
  