Anchor links only working with extension

[Kamik423]

Say I am writing foo.md and I want to reference bar.md. I can reference that file with [](bar.md) or [](bar).
If I now however want to reference the heading heading in bar.md, [](bar.md#heading) works perfectly, but [](bar#heading) does not.

I am using

myst-parser==2.0.0
Sphinx==6.2.1

[welcome]

Thanks for opening your first issue here! Engagement like this is essential for open source projects! 🤗

If you haven't done so already, check out EBP's Code of Conduct. Also, please try to follow the issue template as it helps other community members to contribute more effectively.

If your issue is a feature request, others may react to it, to raise its prominence (see Feature Voting).

Welcome to the EBP community! 🎉