[Feature]: In Container._repr_html_, indicate which fields are links

[rly]

What would you like to see added to HDMF?

Container._repr_html_ is not a replacement for HDFView or another comprehensive HDF5 file explorer, but as I am debugging a subgroup vs link issue, it would be nice if the HTML repr could indicate whether an object is a link, i.e., an object's field is a link if its parent is not the object. Related to NeurodataWithoutBorders/pynwb#1831

What solution would you like?

cc @stephprince - If I understand your changes that add ("link to X") in NeurodataWithoutBorders/pynwb#1831 correctly, I think we can generalize those changes to apply to all links of a container object.

Do you have any interest in helping implement the feature?

No.