bpo-38530: Offer suggestions on NameError (GH-25397)

When printing NameError raised by the interpreter, PyErr_Display
will offer suggestions of simmilar variable names in the function that the exception
was raised from:

    >>> schwarzschild_black_hole = None
    >>> schwarschild_black_hole
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    NameError: name 'schwarschild_black_hole' is not defined. Did you mean: schwarzschild_black_hole?
diff --git a/Include/cpython/pyerrors.h b/Include/cpython/pyerrors.h
index a15082e..9d88e66 100644
--- a/Include/cpython/pyerrors.h
+++ b/Include/cpython/pyerrors.h
@@ -64,6 +64,11 @@ typedef struct {
 
 typedef struct {
     PyException_HEAD
+    PyObject *name;
+} PyNameErrorObject;
+
+typedef struct {
+    PyException_HEAD
     PyObject *obj;
     PyObject *name;
 } PyAttributeErrorObject;