[clang] [Clang] Fix constexpr-ness on implicitly deleted destructors (PR #116359)

[via cfe-commits]

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@@ -158,6 +158,35 @@ C++ Specific Potentially Breaking Changes
 
   Previously, this code was erroneously accepted.
 
+- Clang will now consider the implicitly deleted destructor of a union or
+  a non-union class without virtual base class to be ``constexpr`` in C++20
+  mode. Previously, Clang does so since C++23, but the standard specification
+  for this changed in C++20. (GH#85550)
----------------
cor3ntin wrote:

```suggestion
  mode (Clang 19 only did so in C++23 mode but the standard specification for this changed in C++20). (#GH85550)
```

https://github.com/llvm/llvm-project/pull/116359