bpo-38602: Add fcntl.F_OFD_XXXX for fcntlmodule (GH-16956)

diff --git a/Doc/library/fcntl.rst b/Doc/library/fcntl.rst
index da39c31..5c172b8 100644
--- a/Doc/library/fcntl.rst
+++ b/Doc/library/fcntl.rst
@@ -36,6 +36,8 @@
 .. versionchanged:: 3.9
    On macOS, the fcntl module exposes the ``F_GETPATH`` constant, which obtains
    the path of a file from a file descriptor.
+   On Linux(>=3.15), the fcntl module exposes the ``F_OFD_GETLK``, ``F_OFD_SETLK``
+   and ``F_OFD_SETLKW`` constants, which working with open file description locks.
 
 The module defines the following functions: