Auto merge of #117510 - elichai:patch-3, r=cuviper

Add track_caller to transmute_copy

Currently if `size_of::<Src>() < size_of::<Dst>()` you will see the following error:
```rust
thread 'test' panicked at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/mem/mod.rs:1056:5:
cannot transmute_copy if Dst is larger than Src
```
This fixes it so it will show the invocation location

Author: bors

Diff for: library/core/src/mem/mod.rs

@@ -1054,6 +1054,7 @@ pub const fn copy<T: Copy>(x: &T) -> T {
 /// ```
 #[inline]
 #[must_use]
+#[track_caller]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_stable(feature = "const_transmute_copy", since = "1.74.0")]
 pub const unsafe fn transmute_copy<Src, Dst>(src: &Src) -> Dst {