docs/zh_CN: Add translation zh_CN/doc-guide/index.rst

Add new translation
  Documentation/translations/zh_CN/doc-guide/index.rst
Signed-off-by: Wu XiangCheng <bobwxc@email.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/4a01400c3d65b2f7eb1c1bebd3a0e102ed29208f.1618295149.git.bobwxc@email.cnSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/translations/zh_CN/doc-guide/index.rst

+.. include:: ../disclaimer-zh_CN.rst
+
+:Original: Documentation/doc-guide/index.rst
+
+:译者: 吴想成 Wu XiangCheng <bobwxc@email.cn>
+
+.. _doc_guide_zh:
+
+================
+如何编写内核文档
+================
+
+.. toctree::
+   :maxdepth: 1
+
+   sphinx
+   kernel-doc
+   parse-headers
+   contributing
+   maintainer-profile
+
+.. only::  子项目与HTML
+
+   目录
+   ====
+
+   * :ref:`genindex`