Is your feature request related to a problem? Please describe.

It can often happen that we want to render an object somewhere just to reuse its docstrings, without actually adding this rendered object into the inventory, because its true location is in another API reference page. We want cross-refs to point to the true reference, so we don't want this object to overwrite the cross-ref target.

Describe the solution you'd like

Some option to say "don't add this to the inventory". This would both affect the inventory and the map URLs of autorefs.

Describe alternatives you've considered

/

Additional context

Somewhat related to mkdocstrings/autorefs#25.