[clang] [clang] Factor out OpenACC part of `Sema` (PR #84184)

[Erich Keane via cfe-commits]

================
@@ -1200,6 +1200,27 @@ class Sema final {
   //
   //
 
+  /// \name Sema Components
+  /// Parts of Sema
+  ///@{
+
+  // Just in this section, private members are followed by public, because
+  // C++ requires us to create (private) objects before (public) references.
+
+private:
+  std::unique_ptr<SemaOpenACC> OpenACCPtr;
----------------
erichkeane wrote:

A comment describing how this works would be nice for the folks that come around here in the future.

https://github.com/llvm/llvm-project/pull/84184