fix Sphinx error in os.rst
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index c3dfb3d..74b89b8 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -2294,8 +2294,8 @@
single: directory; walking
single: directory; traversal
- This behaves exactly like :func:`walk`, except that it yields a 4-tuple
- ``(dirpath, dirnames, filenames, dirfd)``.
+ This behaves exactly like :func:`walk`, except that it yields a 4-tuple
+ ``(dirpath, dirnames, filenames, dirfd)``.
*dirpath*, *dirnames* and *filenames* are identical to :func:`walk` output,
and *dirfd* is a file descriptor referring to the directory *dirpath*.