Rollup merge of #126402 - firefighterduck:fix-unsafe-precon-copy, r=Nilstrieb

Fix wrong `assert_unsafe_precondition` message for `core::ptr::copy`

A small fix in the `assert_unsafe_precondition` message for `core::ptr::copy` as described by rust-lang/rust#126400 .

fixes #126400

Author: matthiaskrgr