Miscellaneous doc fixes/enhancements

Change-Id: I915303cea787d9fb188428b98ac6cfc610cc4470
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/docs/firmware-design.rst b/docs/firmware-design.rst
index 06fdbac..d00e45c 100644
--- a/docs/firmware-design.rst
+++ b/docs/firmware-design.rst
@@ -2343,18 +2343,18 @@
 A subscriber that wants to subscribe to event ``foo`` published above would
 implement:
 
-::
+.. code:: c
 
-   void *foo_handler(const void *arg)
-   {
-        void *result;
+    void *foo_handler(const void *arg)
+    {
+         void *result;
 
-        /* Do handling ... */
+         /* Do handling ... */
 
-        return result;
-   }
+         return result;
+    }
 
-   SUBSCRIBE_TO_EVENT(foo, foo_handler);
+    SUBSCRIBE_TO_EVENT(foo, foo_handler);
 
 
 Reclaiming the BL31 initialization code