man/man3/abs.3: Document u{,l,ll,imax}abs()

man/man3/abs.3: Document u{,l,ll,imax}abs()

C2Y adds unsigned versions of the abs functions (see C2Y draft N3467 and
proposal N3349).  Support for these functions will be included in GCC 15
and glibc 2.42.

Link: <https://www.open-std.org/JTC1/SC22/WG14/www/docs/n3467.pdf>
Link: <https://www.open-std.org/JTC1/SC22/WG14/www/docs/n3349.pdf>
Link: <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117024>
Link: <https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=5b132ec2b7712dbc055838b3b538b83ad1196414>
Signed-off-by: Anton Zellerhoff <wg14@ascz.de>
Message-ID: <28a36070fe18707ab9fa26b91c88e6fd87a72097.1744566285.git.wg14@ascz.de>
Signed-off-by: Alejandro Colomar <alx@kernel.org>