doc: move example to the right place

src/vdp_pesi.vcc

@@ -229,7 +229,17 @@ threads required without relevant drawbacks
   request are cacheable, and thus are highly likely to lead to cache
   hits.
 
-XXX ... Also see the discussion below for more detail.
+Example::
+
+  # Activate serial mode at ESI level > 0, if we know that all includes
+  # in the response at this level lead to cacheable responses.
+
+  sub vcl_deliver {
+      pesi.activate();
+      if (req.esi_level > 0 && req.url == "/all/cacheable/includes") {
+          pesi.set(serial, true);
+      }
+  }
 
 ``thread``
 ----------
@@ -293,18 +303,6 @@ the following reasons:
 
 In short, keeping ``thread`` at the default ``true`` should be the
 right option, the alternative exists just in case.
-
-Example::
-
-  # Activate serial mode at ESI level > 0, if we know that all includes
-  # in the response at this level lead to cacheable responses.
-
-  sub vcl_deliver {
-      pesi.activate();
-      if (req.esi_level > 0 && req.url == "/all/cacheable/includes") {
-      	 pesi.set(serial, true);
-      }
-  }
   
 $Function VOID workspace_prealloc(BYTES min_free=4096, INT max_nodes=32)