Replace path with python/Lib

Author: totosuki

Doc/library/os.rst

@@ -3669,7 +3669,7 @@ features:
 
       import os
       from os.path import join, getsize
-      for root, dirs, files in os.walk(os.getcwd()):
+      for root, dirs, files in os.walk("python/Lib"):
           print(root, "consumes", end=" ")
           print(sum(getsize(join(root, name)) for name in files), end=" ")
           print("bytes in", len(files), "non-directory files")