Specify in docs that template variables created e.g. by {%url%} are block-local

[leif_p]

Hi. {% url view_name as var %} seems to create a var whose scope is the block where the tag was called. This is not evident from the documentation, and took me a little while to figure out.

I assume this is the behavior of any other templatetag that lets you create a variable. Maybe you could add a section about scoping in the template system, and then have a link to it from the docs for each templatetag.

I am using Django 1.1 on Google App Engine, if that makes a difference.

[Aymeric Augustin]

Change UI/UX from NULL to False.

[Aymeric Augustin]

Change Easy pickings from NULL to False.

[Tim Graham <timograham@…>]

In 4a5aac47a619a27c2458cfdcba56d53b05c789ad:

Fixed #13116 -- Described scope of variables created by {% url ... as var %} syntax.

Thanks leif_p for the suggestion.

[Tim Graham <timograham@…>]

In 4f058655d0defad179f1a92c7e2d1f282c26b1f0:

[1.6.x] Fixed #13116 -- Described scope of variables created by {% url ... as var %} syntax.

Thanks leif_p for the suggestion.

Backport of 4a5aac47a6 from master