post_wrap tag can be simplified when Django 5.2 is the minimum supported version

[stuartmaxwell]

In April 2026, Django 5.2 will be the lowest supported version of Django: https://www.djangoproject.com/download/

Django 5.2 introduced simple block tags: https://docs.djangoproject.com/en/6.0/howto/custom-template-tags/#simple-block-tags

This will massively simplify the post_wrap template tag which uses the old of way of doing things.