[clang-tools-extra] [clang-tidy] add bugprone-nested-switch-label (PR #212323)

[Yanzuo Liu via cfe-commits]

================
@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "NestedSwitchLabelCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+namespace {
+
+static const char SwitchBodyId[] = "switch-body";
+static const char SwitchLabelId[] = "switch-label";
----------------
zwuis wrote:

Use `StringRef`.

https://github.com/llvm/llvm-project/pull/212323