[LifetimeSafety] provide more details on lifetimebound violation

```cpp
#include

struct S
{
S(const std::vector& v); // missing annotation
};

S f2(const std::vector& v [[clang::lifetimebound]])
{
return {v}; // actual violation location
}

S f1(const std::vector& v [[clang::lifetimebound]])
{
return f2(v);
}
```

```
:8:34: warning: could not verify that the return value can be lifetime bound to 'v' [-Wlifetime-safety-lifetimebound-violation]
8 | S f2(const std::vector& v [[clang::lifetimebound]])
| ^~~~~~~~~~~~~~~~~~~~
```

https://godbolt.org/z/Wex6xaW1n

Start by reproducing the warning with the C++ example and compiler flag shown in the issue, using the linked Godbolt case as the reference. Trace the lifetimebound diagnostic from the reported location in f2; done means the warning provides more useful details about the missing annotation or actual violation while preserving the diagnostic's correctness.

Written by the indexing model from the issue text.