Added deleted copy constructor for error_scope to comply with rule of 3. (#3870)

* Added deleted copy constructor for error_scope to comply with rule of 3.

include/pybind11/detail/common.h

@@ -992,6 +992,7 @@ constexpr const char
 struct error_scope {
 struct error_scope {
     PyObject *type, *value, *trace;
     PyObject *type, *value, *trace;
     error_scope() { PyErr_Fetch(&type, &value, &trace); }
     error_scope() { PyErr_Fetch(&type, &value, &trace); }
+    error_scope(const error_scope &) = delete;
     ~error_scope() { PyErr_Restore(type, value, trace); }
     ~error_scope() { PyErr_Restore(type, value, trace); }
 };
 };