FR: Allow `down:: ![[note]]`

I would like the dataview format to support `down:: ![[note]]` and `(down:: ![[note]])`. This is useful when I want to embed [[note]] and declare the `down` relationship at the same time.

<img width="130" height="112" alt="Image" src="https://github.com/user-attachments/assets/bcf2b910-3341-4c2c-95f2-59effe2774ab" />
