[doc] fix dead link (#8548)

* add en doc

* fix dead link & test=document_fix

* fix dead link & test=document_fix

doc/doc_ch/whl.md

@@ -294,7 +294,7 @@ paddleocr --image_dir PaddleOCR/doc/imgs_words/ch/word_1.jpg --use_angle_cls tru
 
 ## 3 自定义模型
 
-当内置模型无法满足需求时，需要使用到自己训练的模型。 首先，参照[inference.md](./inference.md) 第一节转换将检测、分类和识别模型转换为inference模型，然后按照如下方式使用
+当内置模型无法满足需求时，需要使用到自己训练的模型。 首先，参照[模型导出](./detection.md#4-模型导出与预测)将检测、分类和识别模型转换为inference模型，然后按照如下方式使用
 
 ### 3.1 代码使用
 

doc/doc_en/whl_en.md

@@ -261,7 +261,7 @@ Output will be a list, each item contains classification result and confidence
 
 ## 3 Use custom model
 When the built-in model cannot meet the needs, you need to use your own trained model.
-First, refer to the first section of [inference_en.md](./inference_en.md) to convert your det and rec model to inference model, and then use it as follows
+First, refer to [export](./detection_en.md#4-inference) doc to convert your det and rec model to inference model, and then use it as follows
 
 ### 3.1 Use by code