!900 fix bugs for docs

Merge pull request !900 from yingchen/r0.7

tutorials/source_en/advanced_use/nlp_application.md

@@ -15,7 +15,7 @@
         - [Configuring Environment Information](#configuring-environment-information)
         - [Preprocessing the Dataset](#preprocessing-the-dataset)
         - [Defining the Network](#defining-the-network)
-        - [Pre-Traning](#pre-training)
+        - [Pre-Training](#pre-training)
         - [Defining the Optimizer and Loss Function](#defining-the-optimizer-and-loss-function)
         - [Training and Saving the Model](#training-and-saving-the-model)
         - [Validating the Model](#validating-the-model)

tutorials/source_en/advanced_use/summary_record.md

@@ -342,7 +342,7 @@ For more parameter Settings, see the [MindInsight related commands](https://www.
 
     Right code:
     ```python3
-    ...示例
+    ...
     summary_collector = SummaryCollector('./summary_dir')
     model.train(epoch=2, train_dataset, callbacks=[summary_collector])
     ...