docs: kernel-doc.rst: improve typedef documentation

Add documentation about typedefs for function prototypes and
move it to happen earlier.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/doc-guide/kernel-doc.rst

@@ -282,6 +282,28 @@ The kernel-doc data structure comments describe each member of the structure,
 in order, with the member descriptions.
 
 
+Typedef documentation
+---------------------
+
+The general format of a typedef kernel-doc comment is::
+
+  /**
+   * typedef type_name - Brief description.
+   *
+   * Description of the type.
+   */
+
+Typedefs with function prototypes can also be documented::
+
+  /**
+   * typedef type_name - Brief description.
+   * @arg1: description of arg1
+   * @arg2: description of arg2
+   *
+   * Description of the type.
+   */
+   typedef void (*type_name)(struct v4l2_ctrl *arg1, void *arg2);
+
 
 Highlights and cross-references
 -------------------------------
@@ -384,16 +406,6 @@ on a line of their own, like all other kernel-doc comments::
         int foobar;
   }
 
-Typedef documentation
----------------------
-
-The general format of a typedef kernel-doc comment is::
-
-  /**
-   * typedef type_name - Brief description.
-   *
-   * Description of the type.
-   */
 
 Overview documentation comments
 -------------------------------