docs/zh_CN: two minor fixes in zh_CN/doc-guide/

zh_CN/doc-guide/kernel-doc.rst
  replace a ref tag to solve docs-next warning

zh_CN/doc-guide/parse-headers.rst
  fix an unperfect word

Signed-off-by: Wu XiangCheng <bobwxc@email.cn>
Link: https://lore.kernel.org/r/20210414033435.GA27907@bobwxc.top


Signed-off-by: Jonathan Corbet <corbet@lwn.net>