Fixed some typos and syntax errors in the Twig reference

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | -
You will have to add a label before the "render_esi" headline like this:

```rst
.. _reference-twig-function-render-esi:
```

and then change the referenced label name here accordingly.