panic: refine the document for 'panic_print'

panic: refine the document for 'panic_print'

User reported current document about SYS_INFO_PANIC_CONSOLE_REPLAY is
confusing, that people could expect all user space console messages to be
replayed.

Specify that only 'kernel' messages will be replayed to solve the confusion.

Link: https://lkml.kernel.org/r/20250825025701.81921-3-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Reported-by: Askar Safin <safinaskar@zohomail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>