try to add duplicate warning definition only for knitr

[cderv]

In knitr, warning: 'NA' is supported. How to allow that for auto completion ?

---
title: "test"
format: html
---

```{r}
#| warning: NA
warning("Test")
```

[cderv]

@cscheid Do you know if our schema would allow to get a specific YAML validation for an option in cell

while this option is also used as document-execute.

The way I tried here, seems to have remove the execute part

while correctly added under cell

Normaly warning is also in execute

So do we have a way to have two warning definition with our schema ?

Thank you !