!416 fix the ref format of two files in tutorials

Merge pull request !416 from zhangyi/fix_ref

tutorials/source_zh_cn/advanced_use/nlp_application.md

@@ -22,7 +22,7 @@
 <!-- /TOC -->
 
 <a href="https://gitee.com/mindspore/docs/blob/master/tutorials/source_zh_cn/advanced_use/nlp_application.md" target="_blank"><img src="../_static/logo_source.png"></a>&nbsp;&nbsp;
-<a href="https://gitee.com/mindspore/docs/blob/master/tutorials/notebook/nlp_application.ipynb" target="_blank"><img src="../_static/logo_notebook.png">
+<a href="https://gitee.com/mindspore/docs/blob/master/tutorials/notebook/nlp_application.ipynb" target="_blank"><img src="../_static/logo_notebook.png"></a>
 
 ## 概述
 

tutorials/source_zh_cn/use/data_preparation/data_processing_and_augmentation.md

@@ -17,7 +17,7 @@
 <!-- /TOC -->
 
 <a href="https://gitee.com/mindspore/docs/blob/master/tutorials/source_zh_cn/use/data_preparation/data_processing_and_augmentation.md" target="_blank"><img src="../../_static/logo_source.png"></a>&nbsp;&nbsp;
-<a href="https://gitee.com/mindspore/docs/blob/master/tutorials/notebook/data_loading_enhance/data_loading_enhancement.ipynb" target="_blank"><img src="../../_static/logo_notebook.png">
+<a href="https://gitee.com/mindspore/docs/blob/master/tutorials/notebook/data_loading_enhance/data_loading_enhancement.ipynb" target="_blank"><img src="../../_static/logo_notebook.png"></a>
 
 ## 概述