Allow the {% now %} tag to store its output in the context

[Baptiste Mispelon]

I hit this issue when trying to use the value of the current year inside a translated string.

Normally, you'd do something like this:

{% blocktrans %}Current year: {% now 'Y' %}{% endblocktrans %}

But this doesn't work because blocktrans doesn't allow other tags inside.

So I propose adding the as varname syntax to {% now %} so you can do something like this:

{% now 'Y' as current_year %}
{% blocktrans %}Current year: {{ current_year }}{% endblocktrans %}

[Baptiste Mispelon]

PR here: ​https://github.com/django/django/pull/3621

[Baptiste Mispelon <bmispelon@…>]

In c335c0fee92a658b6a09453ae73e5c542f10703a:

Fixed #23914 -- Improved {% now %} to allow storing its result in the context.

Thanks to Tim for the review.