GitHub CI clang-tidy fixes.

tests/test_multiple_inheritance.cpp

@@ -64,7 +64,7 @@ namespace {
     struct I801C : I801B1, I801B2 {};
     struct I801D : I801C {}; // Indirect MI
 
-} // namespace anonymous
+} // namespace
 
 PYBIND11_SMART_POINTER_HOLDER_TYPE_CASTERS(Base1a, std::shared_ptr<Base1a>)
 PYBIND11_SMART_POINTER_HOLDER_TYPE_CASTERS(Base2a, std::shared_ptr<Base2a>)

tests/test_smart_ptr.cpp

@@ -269,7 +269,7 @@ namespace {
         void add(std::shared_ptr<ElementBase> e) { l.push_back(e); }
         std::vector<std::shared_ptr<ElementBase>> l;
     };
-}
+} // namespace
 
 PYBIND11_SMART_POINTER_HOLDER_TYPE_CASTERS(Object, ref<Object>)
 PYBIND11_SMART_POINTER_HOLDER_TYPE_CASTERS(MyObject1, ref<MyObject1>)