message: docfix: fix docstring error in KerasHistory
diff: @@ -2758,7 +2758,7 @@ class KerasHistory(
  layer: The Layer that produced the Tensor.
  node_index: The specific call to the Layer that produced this Tensor. Layers
  can be called multiple times in order to share weights. A new node is
  - created every time a Tensor is called.
  + created every time a Layer is called.
  tensor_index: The output index for this Tensor. Always zero if the Layer
  that produced this Tensor only has one output. Nested structures of
  Tensors are deterministically assigned an index via `nest.flatten`.
  