Added template syntax highlighting in docs/topics/i18n/timezones.txt.

docs/topics/i18n/timezones.txt

@@ -251,6 +251,8 @@ output for computers rather than for humans. The following filters and tags,
 provided by the ``tz`` template tag library, allow you to control the time zone
 conversions.
 
+.. highlight:: html+django
+
 Template tags
 -------------
 
@@ -366,6 +368,8 @@ For example::
 
     {{ value|timezone:"Europe/Paris" }}
 
+.. highlight:: python
+
 .. _time-zones-migration-guide:
 
 Migration guide