Documentation: Update path to sysrq.txt

Commit 9d85025b0418 ("docs-rst: create an user's manual book") moved the
sysrq.txt leaving old paths in the kernel docs.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index a32b4b7..bac23c1 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -85,7 +85,7 @@
 - softlockup_all_cpu_backtrace
 - soft_watchdog
 - stop-a                      [ SPARC only ]
-- sysrq                       ==> Documentation/sysrq.txt
+- sysrq                       ==> Documentation/admin-guide/sysrq.rst
 - sysctl_writes_strict
 - tainted
 - threads-max