[dvipdfmx] referencing an link annotation

[Ulrike Fischer]

> I think there was a similar request posted to the dvipdfmx list
> for extending pdf:bann to support reference ID.

> https://tug.org/pipermail/dvipdfmx/2020-July/000080.html

> As I responded above such extension was already done.

Oh sorry. I have clearly completly pushed this out of my mind. I will 
test asap. Thanks!

-- 
Mit freundlichen Grüßen
Ulrike Fischer