message: [XLA] Decrease intensity of "XLA is experimental" warning in docs.
diff: <img style="width:50%" src="./images/xlalogo.png">
  </div>
  -> Note: XLA is experimental and considered alpha. Most use cases will not
  -> see improvements in performance (speed or decreased memory usage). We have
  -> released XLA early so the Open Source Community can contribute to its
  -> development, as well as create a path for integration with hardware
  -> accelerators.
  +> Note: XLA is still under development. Some use cases will not
  +> see improvements in speed or decreased memory usage.
  XLA (Accelerated Linear Algebra) is a domain-specific compiler for linear
  algebra that optimizes TensorFlow computations. The results are improvements in
  