Fix .rst formatting

Author: mpdude

templating/twig_extension.rst

@@ -53,7 +53,7 @@ As an example you'll create a price filter to format a given number into price::
 
 .. note::
 
-    Prior to Twig 1.26, your extension had to provide an additional `getName` method that 
+    Prior to Twig 1.26, your extension had to provide an additional ``getName`` method that 
     returned the extension's internal name. When your extension needs to be compatible
     with Twig versions before 1.26, include this method which is omitted in the example 
     above.