Reword isinstance/subclass checks (python#12)

Author: emmatyping

Objects/descrobject.c

@@ -2098,15 +2098,15 @@ static PyObject *
 ga_instancecheck(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
     return PyErr_Format(PyExc_TypeError,
-                        "TypeError: Subscripted generics cannot be used with class and instance checks",
+                        "isinstance() argument 2 cannot be a parameterized generic",
                         self);
 }
 
 static PyObject *
 ga_subclasscheck(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
     return PyErr_Format(PyExc_TypeError,
-                        "TypeError: Subscripted generics cannot be used with class and instance checks",
+                        "issubclass() argument 2 cannot be a parameterized generic",
                         self);
 }