There is a small error in the ./docs/data_config.md and ./docs/data_config_en.md respectively. #29

for the ./docs/data_config.md file : "TREC 1 2 问题分类数据集下载到.data/imdb" may be "TREC 1 2 问题分类数据集下载到.data/trec"

for the ./docs/data_config_en.md file : "Download TREC Question Classification 2 dataset to .data/imdb" may be "Download TREC Question Classification 2 dataset to .data/trec"

In general, "imdb" may be replaced by "trec".