message: Updated docs formatting
  tf.feature_column.categorical_column_with_vocabulary_file defined in python/feature_column/feature_column_v2.py.
diff: @@ -1589,7 +1589,7 @@ def categorical_column_with_vocabulary_file_v2(key,
  and `''` for string, which will be dropped by this feature column.
  Example with `num_oov_buckets`:
  - File '/us/states.txt' contains 50 lines, each with a 2-character U.S. state
  + File `'/us/states.txt'` contains 50 lines, each with a 2-character U.S. state
  abbreviation. All inputs with values in that file are assigned an ID 0-49,
  corresponding to its line number. All other values are hashed and assigned an
  ID 50-54.
  @@ -1604,8 +1604,8 @@ def categorical_column_with_vocabulary_file_v2(key,
  ```
  Example with `default_value`:
  - File '/us/states.txt' contains 51 lines - the first line is 'XX', and the
  - other 50 each have a 2-character U.S. state abbreviation. Both a literal 'XX'
  + File `'/us/states.txt'` contains 51 lines - the first line is `'XX'`, and the
  + other 50 each have a 2-character U.S. state abbreviation. Both a literal `'XX'`
  in input, and other values missing from the file, will be assigned ID 0. All
  others are assigned the corresponding line number 1-50.
  