Issue 2947: document how return code handling translates from
os.popen to subprocess.  Also fixes reference link in the
os.spawn documentation.
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index fc6f654..4dcb8591 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -1715,8 +1715,8 @@
 
    (Note that the :mod:`subprocess` module provides more powerful facilities for
    spawning new processes and retrieving their results; using that module is
-   preferable to using these functions.  Check specially the *Replacing Older
-   Functions with the subprocess Module* section in that documentation page.)
+   preferable to using these functions.  Check especially the
+   :ref:`subprocess-replacements` section.)
 
    If *mode* is :const:`P_NOWAIT`, this function returns the process id of the new
    process; if *mode* is :const:`P_WAIT`, returns the process's exit code if it