Merge pull request django-cms#4180 from driesdesmet/patch-2

missing import in code example, documentation

Author: yakky

docs/how_to/extending_page_title.rst

@@ -109,6 +109,7 @@ Simplified toolbar API
 
 Since 3.0.6 a simplified toolbar API is available to handle the more common cases::
 
+    from cms.toolbar_pool import toolbar_pool
     from cms.extensions.toolbar import ExtensionToolbar
     from django.utils.translation import ugettext_lazy as _
     from .models import IconExtension