Auto merge of #102732 - RalfJung:assert_unsafe_precondition2, r=bjorn3

nicer errors from assert_unsafe_precondition

This makes the errors shown by cargo-careful nicer, and since `panic_no_unwind` is `nounwind noreturn` it hopefully doesn't have bad codegen impact. Thanks to `@bjorn3` for the hint!

Would be nice if we could somehow supply our own (static) message to print, currently it always prints `panic in a function that cannot unwind`. But still, this is better than before.

Author: bors

crates/hir-def/src/builtin_attr.rs

@@ -379,7 +379,7 @@ pub const INERT_ATTRIBUTES: &[BuiltinAttribute] = &[
     // ==========================================================================
 
     rustc_attr!(rustc_allocator, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
-    rustc_attr!(rustc_allocator_nounwind, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
+    rustc_attr!(rustc_nounwind, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
     gated!(
         alloc_error_handler, Normal, template!(Word), WarnFollowing,
         experimental!(alloc_error_handler)