Take this document

````markdown
---
format: gfm
---

::: {.content-visible when-format="gfm"}
Should be shown
:::

Some other text
````

This will not work because our `gfm` format is build on `commonmark`. 
https://github.com/quarto-dev/quarto-cli/blob/8ad60b0cf6990c34afc20b3e04609496793406d3/src/format/markdown/format-markdown.ts#L46-L55

So this will work 
````markdown
---
format: gfm
---

::: {.content-visible when-format="commonmark"}
Should be shown
:::

Some other text

````

and our global alias too 
````markdown
---
format: gfm
---

::: {.content-visible when-format="markdown"}
Should be shown
:::

Some other text
````

We should probably correctly alias our format name, shouldn't we ? 
cscheid
2023-02-17T16:40:00Z
cderv
bug
v1.4
open
Conditional content should alias the user facing format name
https://github.com/quarto-dev/quarto-cli/issues/4411