Updated TEMPLATE_CONTEXT_PROCESSORS defaults in the docs.

django.core.context_processors.tz was missing from default
TEMPLATE_CONTEXT_PROCESSORS in the template api documentation.

docs/ref/templates/api.txt

@@ -370,6 +370,7 @@ and return a dictionary of items to be merged into the context. By default,
     "django.core.context_processors.i18n",
     "django.core.context_processors.media",
     "django.core.context_processors.static",
+    "django.core.context_processors.tz",
     "django.contrib.messages.context_processors.messages")
 
 In addition to these, ``RequestContext`` always uses