message: Update docs for `double` support on `tf.decode_csv`
diff: @@ -1183,7 +1183,7 @@ def decode_csv(records, record_defaults, field_delim=",",
  Each string is a record/row in the csv and all records should have
  the same format.
  record_defaults: A list of `Tensor` objects with specific types.
  - Acceptable types are `float32`, `int32`, `int64`, `string`.
  + Acceptable types are `float32`, `float64`, `int32`, `int64`, `string`.
  One tensor per column of the input record, with either a
  scalar default value for that column or empty if the column is required.
  field_delim: An optional `string`. Defaults to `","`.
  