Documentation/sysctl: coredump: add %F for pidfd number

JIRA: https://issues.redhat.com/browse/RHEL-107520

commit 0400a54
Author: Salvatore Bonaccorso <carnil@debian.org>
Date:   Thu, 12 Jun 2025 08:02:04 +0200

    Documentation/sysctl: coredump: add %F for pidfd number

    In commit b5325b2 ("coredump: hand a pidfd to the usermode coredump
    helper") a new core_pattern specifier, %F, was added to provide a pidfs
    to the usermode helper process referring to the crashed process.

    Update the documentation to include the new core_pattern specifier.

    Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
    Signed-off-by: Jonathan Corbet <corbet@lwn.net>
    Link: https://lore.kernel.org/r/20250612060204.1159734-1-carnil@debian.org

Signed-off-by: Waiman Long <longman@redhat.com>

Author: Waiman-Long

Documentation/admin-guide/sysctl/kernel.rst

@@ -170,6 +170,7 @@ core_pattern
 	%E		executable path
 	%c		maximum size of core file by resource limit RLIMIT_CORE
 	%C		CPU the task ran on
+	%F		pidfd number
 	%<OTHER>	both are dropped
 	========	==========================================