Retain comments

Author: snarang181

clang/include/clang/AST/DeclContextInternals.h

@@ -177,6 +177,8 @@ class StoredDeclsList {
       if (ND->isFromASTFile())
         return true;
       return llvm::any_of(Decls, [ND](NamedDecl *D) {
+        // Only replace the local declaration if the external declaration has
+        // higher visiblities.
         return D->getModuleOwnershipKind() <= ND->getModuleOwnershipKind() &&
                D->declarationReplaces(ND, /*IsKnownNewer=*/false);
       });