doxygen: reorganize directory structure

.gitee/PULL_REQUEST_TEMPLATE.en.md

@@ -27,4 +27,4 @@ As part of this pull request, I've considered the following:
 - [ ] All modifications to BSP are justified and do not affect other components or BSPs.
 - [ ] I've commented appropriately where code is tricky.
 - [ ] Code in this PR is of high quality.
-- [ ] This PR complies with [RT-Thread code specification](https://gitee.com/rtthread/rt-thread/blob/master/documentation/contribution_guide/coding_style_en.md)
+- [ ] This PR complies with [RT-Thread code specification](https://gitee.com/rtthread/rt-thread/blob/master/documentation/7.contribution/coding_style_en.md)

.gitee/PULL_REQUEST_TEMPLATE.zh-CN.md

@@ -27,4 +27,4 @@
 - [ ] 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或
 - [ ] 对难懂代码均提供对应的注释
 - [ ] 本拉取/合并请求代码是高质量的
-- [ ] 本拉取/合并符合[RT-Thread代码规范](https://gitee.com/rtthread/rt-thread/blob/master/documentation/contribution_guide/coding_style_cn.md)
+- [ ] 本拉取/合并符合[RT-Thread代码规范](https://gitee.com/rtthread/rt-thread/blob/master/documentation/7.contribution/coding_style_cn.md)

documentation/Doxyfile

@@ -923,7 +923,7 @@ RECURSIVE              = YES
 EXCLUDE                = ./0.doxygen/mainpage.h \
                          ./2.quick-start/quick_start_qemu \
                          ./env/env-vscode.md \
-                         ./contribution_guide/coding_style_cn.md
+                         ./7.contribution/coding_style_cn.md
 
 # The EXCLUDE_SYMLINKS tag can be used to select whether or not files or
 # directories that are symbolic links (a Unix file system feature) are excluded