Stop UI "dead ends", Tell which path is already in use, not just "path is already in use"

When a user enters a path alias that already exists, they receive a "Path is already in use" error.

However this leads to a user experience dead end.

https://uxmag.com/articles/usability-tip-no-dead-ends-please

It is currently almost impossible for the user to know which other node/entity/etc is using that alias, in our case the user tried to search for a similar node title but could not be found - because the other node using that alias had a very different title, compounded with the fact there are thousands of nodes on the site.