Special content modes fail silently

[jassielof]

As reference:

https://forum.typst.app/t/how-to-interpret-hayagriva-data-as-content-instead-of-strings/3865

And a recent Discord issue:

https://discord.com/channels/1054443721975922748/1088371919725793360/1520869299970113669

As @cady-b said:

https://discord.com/channels/1054443721975922748/1088371919725793360/1520870526338338846

It probably should give an error though instead of failing silently; or at least a warning if fallback is desired, one can always escape the equation to make it stop complaining 😅