* Add symbolic link from Paddle/CONTRIBUTING.md to doc/howto/dev/contribute_to_paddle_en.md so sphinx can generate the document

* Update CONTRIBUTING.md links so sphinx does not add these links to the TOC
* Removed dev/contribute_to_paddle_cn.md from documentation, since this document is not in sync with Paddle/CONTRIBUTING.md

Author: cs2be

CONTRIBUTING.md

@@ -151,12 +151,7 @@ python \
 
 This will enable VLOG messages generated by `buddy_allocator.{h,cc}` and in the verbose range of 0 to 3, so you will see above example VLOG message, which is in level 3.  This suggests that we output overall messages in lower verbose levels, so they display with higher probability.  When coding C++, please follow the verbose level convention as follows:
 
-- verbose level 1:
-  - [framework](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/framework)
-- verbose level 3:
-  - [operators](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/operators)
-- verbose level 5:
-  - [memory](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/memory)
-  - [platform](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/platform)
-- verbose level 7:
-  - [math](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/math)
+- verbose level 1: [framework](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/framework)
+- verbose level 3: [operators](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/operators)
+- verbose level 5: [memory](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/memory), [platform](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/platform)
+- verbose level 7: [math](https://github.com/PaddlePaddle/Paddle/tree/develop/paddle/math)

doc/howto/dev/contribute_to_paddle_en.md

@@ -0,0 +1 @@
+../../../CONTRIBUTING.md

doc/howto/index_cn.rst

@@ -21,7 +21,6 @@
 
   dev/build_cn.rst
   dev/write_docs_cn.rst
-  dev/contribute_to_paddle_cn.md
 
 模型配置
 --------