[clang-tools-extra] [clang-tidy] Improve performance-enum-size to exclude empty enums (PR #71640)

[Congcong Cai via cfe-commits]

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@@ -23,6 +23,10 @@ namespace clang::tidy::performance {
 
 namespace {
 
+AST_MATCHER(EnumDecl, hasEnumerators) {
+  return Node.enumerator_begin() != Node.enumerator_end();
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HerrCai0907 wrote:

```suggestion
  return !Node.enumerators().empty();
```

https://github.com/llvm/llvm-project/pull/71640