bpo-43677: Fix a minor error in Doc/howto/descriptor.rst (GH-25123) (#25140)

Author: miss-islington

Doc/howto/descriptor.rst

@@ -1054,7 +1054,7 @@ roughly equivalent to:
 .. testcode::
 
     class MethodType:
-        "Emulate Py_MethodType in Objects/classobject.c"
+        "Emulate PyMethod_Type in Objects/classobject.c"
 
         def __init__(self, func, obj):
             self.__func__ = func