Documentation: doc-guide: use '%' constant indicator in Return: examples

Use the 'constant' indicator '%' in the examples for the
Return: values syntax. This can help encourage people to use it.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/lkml/20221121154358.36856ca6@gandalf.local.home/Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230703232030.8223-1-rdunlap@infradead.org

Documentation/doc-guide/kernel-doc.rst

@@ -151,9 +151,9 @@ named ``Return``.
      line breaks, so if you try to format some text nicely, as in::
 
 	* Return:
-	* 0 - OK
-	* -EINVAL - invalid argument
-	* -ENOMEM - out of memory
+	* %0 - OK
+	* %-EINVAL - invalid argument
+	* %-ENOMEM - out of memory
 
      this will all run together and produce::
 
@@ -163,8 +163,8 @@ named ``Return``.
      ReST list, e. g.::
 
       * Return:
-      * * 0		- OK to runtime suspend the device
-      * * -EBUSY	- Device should not be runtime suspended
+      * * %0		- OK to runtime suspend the device
+      * * %-EBUSY	- Device should not be runtime suspended
 
   #) If the descriptive text you provide has lines that begin with
      some phrase followed by a colon, each of those phrases will be taken