Restore CommentDiagnostic.h and module.modulemap.

Author: kazutakahirata

clang/include/clang/AST/CommentDiagnostic.h

@@ -0,0 +1,15 @@
+//===--- CommentDiagnostic.h - Diagnostics for the AST library --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_COMMENTDIAGNOSTIC_H
+#define LLVM_CLANG_AST_COMMENTDIAGNOSTIC_H
+
+#include "clang/Basic/DiagnosticComment.h"
+
+#endif
+

clang/include/module.modulemap

@@ -111,6 +111,7 @@ module Clang_Diagnostics {
   module All { header "clang/Basic/AllDiagnostics.h" export * }
   module Analysis { textual header "clang/Analysis/Analyses/UnsafeBufferUsageGadgets.def" }
   module AST { header "clang/AST/ASTDiagnostic.h" export * }
+  module Comment { header "clang/AST/CommentDiagnostic.h" export * }
   module Driver { header "clang/Driver/DriverDiagnostic.h" export * }
   module Frontend { header "clang/Frontend/FrontendDiagnostic.h" export * }
   module Lex { header "clang/Lex/LexDiagnostic.h" export * }