timeout: add -f and -p short options as per POSIX 2024

timeout: add -f and -p short options as per POSIX 2024

* src/timeout.c: Support -f and -p short options, corresponding to
--foreground and --preserve-status respectively.  This adds
compatability with POSIX 2024 and OpenBSD.
(usage): Separate translations, and reorder the option descriptions.
* doc/coreutils.texi (timeout invocation): Adjust accordingly,
and also reorder the option descriptions alphabetically.
* tests/timeout/timeout.sh: Also test short option variants.