Change comment as suggested by @rainwoodman.

tests/pybind11_tests.h

@@ -57,7 +57,7 @@ union IntFloat {
 class UnusualOpRef {
 public:
     using NonTrivialType = std::shared_ptr<int>; // Almost any non-trivial type will do.
-    // UNUSUAL operators:
+    // Overriding operator& should not break pybind11.
     NonTrivialType operator&() { return non_trivial_member; }
     const NonTrivialType operator&() const { return non_trivial_member; }