pythongh-70393: Clarify mention of "middle" scope

Doc/tutorial/classes.rst

@@ -124,7 +124,7 @@ directly accessible:
 * the outermost scope (searched last) is the namespace containing built-in names
 
 If a name is declared global, then all references and assignments go directly to
-the middle scope containing the module's global names.  To rebind variables
+the next-to-last scope containing the module's global names.  To rebind variables
 found outside of the innermost scope, the :keyword:`nonlocal` statement can be
 used; if not declared nonlocal, those variables are read-only (an attempt to
 write to such a variable will simply create a *new* local variable in the