Add inline partials with Jinja2

[kummerer94]

Hi,

in the company I work for, we were quite frustrated with the state of inline partials using Jinja2. While there are some brillant people helping with great code snippets (we linked to them), there are some limitations that make working with the existing fragment libraries in Django difficult.

What was particularly annoying was being unable to use TemplateResponse() or having to setup the environment etc. for Jinja2 again. Something that the jinja2 template backend already does today.

We had the idea to copy the existing Django Jinja2 backend and make some modifications so that it supports inline partials by rendering only specific blocks of the template.

One could certainly make the point that using the context to specify the blocks that should be rendered is not the cleanest solution, it was the best solution we could come up with that needed minimal changes to existing code or existing best practices / usecases.

All the code that is necessary for our solution to work is included in the inline_partials_jinja2.rst article.

Please let me know what could be better as this is the first time I have worked with rst as a format.

Best
Alex