Rollup merge of #146182 - ChayimFriedman2:ns-probe, r=jackh726

Don't require next-solver `ProbeRef` to be `Copy`

rust-analyzer would like to use a non-interned `Probe` there.

Also rename it to `Probe` for this reason.

We can make it `Copy` (although then `Probe` will need to be `Clone` for rust-analyzer) but it seems just non-needed.

r? types

Author: jhpratt