Mark deprecated modules as such.
diff --git a/Doc/library/posixfile.rst b/Doc/library/posixfile.rst
index ec58b94..5ed3483 100644
--- a/Doc/library/posixfile.rst
+++ b/Doc/library/posixfile.rst
@@ -7,6 +7,7 @@
 .. module:: posixfile
    :platform: Unix
    :synopsis: A file-like object with support for locking.
+   :deprecated:
 .. moduleauthor:: Jaap Vermeulen
 .. sectionauthor:: Jaap Vermeulen