Cherry-pick 3 commits from release/2.6 to dygraph (#8821)

* Fix typo and grammatical error (#8785)

* Fix broken link to install paddlepaddle (#8729)

The link provided for installing paddlepaddle doesn't work. Hence, this change updates the broken link to install paddlepaddle for CPU and GPU.

* Fix: broken link for whl package documentation. (#8719)

This proposed change fixes the broken link under the section `2.4 Parameter Description` in the last line that says:
Most of the parameters are consistent with the PaddleOCR whl package, see `whl package documentation`.

doc/doc_en/quickstart_en.md

@@ -28,13 +28,13 @@
 - If you have CUDA 9 or CUDA 10 installed on your machine, please run the following command to install
 
   ```bash
-  python3 -m pip install paddlepaddle-gpu -i https://mirror.baidu.com/pypi/simple
+  python -m pip install paddlepaddle-gpu -i https://pypi.tuna.tsinghua.edu.cn/simple
   ```
 
 - If you have no available GPU on your machine, please run the following command to install the CPU version
 
   ```bash
-  python3 -m pip install paddlepaddle -i https://mirror.baidu.com/pypi/simple
+  python -m pip install paddlepaddle -i https://pypi.tuna.tsinghua.edu.cn/simple
   ```
 
 For more software version requirements, please refer to the instructions in [Installation Document](https://www.paddlepaddle.org.cn/install/quick) for operation.

ppstructure/docs/quickstart_en.md

@@ -311,7 +311,7 @@ Please refer to: [Key Information Extraction](../kie/README.md) .
 | save_pdf    | Whether to convert docx to pdf when recovery| False |
 | structure_version |  Structure version, optional PP-structure and PP-structurev2  | PP-structure |
 
-Most of the parameters are consistent with the PaddleOCR whl package, see [whl package documentation](../../doc/doc_en/whl.md)
+Most of the parameters are consistent with the PaddleOCR whl package, see [whl package documentation](../../doc/doc_en/whl_en.md)
 
 <a name="3"></a>
 ## 3. Summary

ppstructure/kie/README.md

@@ -89,7 +89,7 @@ Boxes of different colors in the image represent different categories.
 
 The invoice and application form images have three categories: `request`, `answer` and `header`. The `question` and 'answer' can be used to extract the relationship.
 
-For the ID card image, the mdoel can be directly identify the key information such as `name`, `gender`, `nationality`, so that the subsequent relationship extraction process is not required, and the key information extraction task can be completed using only on model.
+For the ID card image, the model can directly identify the key information such as `name`, `gender`, `nationality`, so that the subsequent relationship extraction process is not required, and the key information extraction task can be completed using only on model.
 
 ### 3.2 RE