[clang-tools-extra] [clang-doc] Improve performance by adding a short circuit (PR #96809)

[Paul Kirth via cfe-commits]

================
@@ -53,30 +80,34 @@ template <typename T> bool MapASTVisitor::mapDecl(const T *D) {
 }
 
 bool MapASTVisitor::VisitNamespaceDecl(const NamespaceDecl *D) {
-  return mapDecl(D);
+  return mapDecl(D, true);
----------------
ilovepi wrote:

for constant params you should have a comment, per our style guide.
```suggestion
  return mapDecl(D, /*isDefinition=*/true);
```

https://github.com/llvm/llvm-project/pull/96809