message: Update add_weight docstring to remove reference to variable_scope.
diff: @@ -289,16 +289,14 @@ class Layer(module.Module):
  name: Variable name.
  shape: Variable shape. Defaults to scalar if unspecified.
  dtype: The type of the variable. Defaults to `self.dtype` or `float32`.
  - initializer: initializer instance (callable).
  - regularizer: regularizer instance (callable).
  - trainable: whether the variable should be part of the layer's
  + initializer: Initializer instance (callable).
  + regularizer: Regularizer instance (callable).
  + trainable: Boolean, whether the variable should be part of the layer's
  "trainable_variables" (e.g. variables, biases)
  - or "non_trainable_variables" (e.g. BatchNorm mean, stddev).
  - Note, if the current variable scope is marked as non-trainable
  - then this parameter is ignored and any added variables are also
  - marked as non-trainable. `trainable` defaults to `True` unless
  - `synchronization` is set to `ON_READ`.
  - constraint: constraint instance (callable).
  + or "non_trainable_variables" (e.g. BatchNorm mean and variance).
  + Note that `trainable` cannot be `True` if `synchronization`
  + is set to `ON_READ`.
  + constraint: Constraint instance (callable).
  partitioner: Partitioner to be passed to the `Trackable` API.
  use_resource: Whether to use `ResourceVariable`.
  synchronization: Indicates when a distributed a variable will be
  