message: [docs] fix function name in bigquery tutorial
  format notebook
diff: "from tensorflow_io.bigquery import BigQueryClient\n",
  "from tensorflow_io.bigquery import BigQueryReadSession\n",
  " \n",
  - "def transofrom_row(row_dict):\n",
  + "def transform_row(row_dict):\n",
  " # Trim all string tensors\n",
  " trimmed_dict = { column:\n",
  " (tf.strings.strip(tensor) if tensor.dtype == 'string' else tensor) \n",
  " requested_streams=2)\n",
  " \n",
  " dataset = read_session.parallel_read_rows()\n",
  - " transformed_ds = dataset.map (transofrom_row)\n",
  + " transformed_ds = dataset.map(transform_row)\n",
  " return transformed_ds\n"
  ]
  },
  