How to add text on cell opening line in gfm format

[kylebutts]

Description

I am using quarto rendering a .qmd file to a gfm format. The quarto document is only a part of my pipeline and I want to use the resultant .md file with Astro.js and [https://expressive-code.com/key-features/text-markers/](Expressive Code).
For that reason, I want the output cells to be "```r " + some additional text.
For example, I want to be able to write this:

``` r del={2} ins={3-4} {6}

```

Is that possible?

[mcanouil]

Could you set a meaningful title?

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A LUA filter is probably what you need.