[3.13] pythonGH-109975: Copyedit 3.13 What's New: Improved Modules (pythonGH-123132)

(cherry picked from commit 127660b)

Co-authored-by: Adam Turner <[email protected]>
Co-authored-by: Hugo van Kemenade <[email protected]>

Author: AA-Turner

Doc/library/os.rst

@@ -3862,6 +3862,8 @@ features:
    .. versionadded:: 3.10
 
 
+.. _os-timerfd:
+
 Timer File Descriptors
 ~~~~~~~~~~~~~~~~~~~~~~