[Clang][AST][NFC] Resolve FIXME: Make CXXRecordDecl *Record const.

Differential Revision: https://reviews.llvm.org/D107477

clang/include/clang/AST/ComparisonCategories.h

@@ -115,8 +115,7 @@ private:
 public:
   /// The declaration for the comparison category type from the
   /// standard library.
-  // FIXME: Make this const
-  CXXRecordDecl *Record = nullptr;
+  const CXXRecordDecl *Record = nullptr;
 
   /// The Kind of the comparison category type
   ComparisonCategoryType Kind;