Mismatching between data mode description and the corresponding code in...

Mismatching between data mode description and the corresponding code in demo\sequence_labeling\README.md (#1761)

* Matching mistaken between demo\sequence_labeling\README.md and demo\sequence_labeling\train.py

* Matching mistaken between demo\text_classification\README.md and demo\text_classification\train.py

* Mismatching between data mode description and the corresponding code in demo\sequence_labeling\README.md