sphinx.rst: Add note about code snippets embedded in the text

There's a paragraph that explains how to create fixed width text block,
but it doesn't explains how to create fixed width text inline, although
this feature is really used through the documentation. Fix that adding a
quick note about it.

Signed-off-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/doc-guide/sphinx.rst

@@ -217,7 +217,7 @@ Here are some specific guidelines for the kernel documentation:
   examples, etc.), use ``::`` for anything that doesn't really benefit
   from syntax highlighting, especially short snippets. Use
   ``.. code-block:: <language>`` for longer code blocks that benefit
-  from highlighting.
+  from highlighting. For a short snippet of code embedded in the text, use \`\`.
 
 
 the C domain