docs/zh_CN/rust: Update the translation of coding-guidelines to 6.9-rc4

Update to commit bc2e7d5 ("rust: support `srctree`-relative links")

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/e83b5dd929371d42889b19750e5e0385544e170f.1714113680.git.siyanteng@loongson.cn

Documentation/translations/zh_CN/rust/coding-guidelines.rst

@@ -157,6 +157,18 @@ https://commonmark.org/help/
 
 	https://doc.rust-lang.org/rustdoc/how-to-write-documentation.html
 
+此外，内核支持通过在链接目标前添加 ``srctree/`` 来创建相对于源代码树的链接。例如:
+
+.. code-block:: rust
+
+       //! C header: [`include/linux/printk.h`](srctree/include/linux/printk.h)
+
+或者:
+
+.. code-block:: rust
+
+       /// [`struct mutex`]: srctree/include/linux/mutex.h
+
 
 命名
 ----