message: Document several optional dependencies of knn
diff: @@ -44,7 +44,8 @@ class KNearestNeighbors:
  Otherwise, neighbors are returned in an arbitrary order. Defaults to True.
  enable_autodiff (bool): if the input is a torch.tensor, jax.numpy.ndarray or tensorflow.Tensor, this
  instructs the function to compute distances in a way that works with automatic differentiation.
  - This is experimental and not supported for all metrics. Defaults to False.
  + This is experimental, not supported for all metrics, and requires the package EagerPy.
  + Defaults to False.
  kwargs: additional parameters are forwarded to the backends.
  """
  self.k = k
  