Added new tag

Author: wouterj

reference/twig_reference.rst

@@ -134,6 +134,9 @@ Filters
 Tags
 ----
 
+.. versionadded:: 2.3
+ The stopwatch tag was added in Symfony 2.3
+
 +---------------------------------------------------+--------------------------------------------------------------------+
 | Tag Syntax | Usage |
 +===================================================+====================================================================+
@@ -150,6 +153,9 @@ Tags
 | ``{% trans_default_domain language %}`` | This will set the default domain for message catalogues in the |
 | | current template |
 +---------------------------------------------------+--------------------------------------------------------------------+
+| ``{% stopwatch name %}...{% endstopwatch %}`` | This will time the run time of the code inside it and put that on |
+| | the timeline of the WebDeveloperBundle. |
++---------------------------------------------------+--------------------------------------------------------------------+
 
 Tests
 -----