[clang] [clang] Implement P2582R1: CTAD from inherited constructors (PR #98788)

[Erich Keane via cfe-commits]

================
@@ -1960,24 +1960,44 @@ class ExplicitSpecifier {
 class CXXDeductionGuideDecl : public FunctionDecl {
   void anchor() override;
 
+public:
+  // Represents the relationship between this deduction guide and the
+  // deduction guide that it was generated from (or lack thereof).
+  // See the SourceDeductionGuide member for more details.
+  enum class SourceDeductionGuideKind : unsigned char {
----------------
erichkeane wrote:

```suggestion
  enum class SourceDeductionGuideKind : uint8_t {
```

I thought I saw elsewhere we do this reasonably consistently?  Else, feel free to ignore.

https://github.com/llvm/llvm-project/pull/98788