message: Fix comment: OperatorPDCholesky -> LinearOperatorTriL
diff: @@ -525,8 +525,8 @@ def matrix_diag_transform(matrix, transform=None, name=None):
  # valid Cholesky factor.
  chol = matrix_diag_transform(matrix, transform=tf.nn.softplus)
  - # OperatorPDCholesky ignores the upper triangle.
  - operator = OperatorPDCholesky(chol)
  + # LinearOperatorTriL ignores the upper triangle.
  + operator = LinearOperatorTriL(chol)
  ```
  Example of heteroskedastic 2-D linear regression.
  