Documentation: fix doc link to fault-injection.rst

Fix incorrect reference to fault-injection docs

Link: https://lkml.kernel.org/r/20250215105106.734-1-ujwal.kundur@gmail.com


Signed-off-by: Ujwal Kundur <ujwal.kundur@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>