[PATCH] manual: Use string values for glibc.cpu.x86_shstk in tunables example

The documentation for system-wide tunables had an example for
overridability that used 0/1 as values for glibc.cpu.x86_shstk.  Use the
correct on/off string values instead.
---
 manual/tunables.texi | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/manual/tunables.texi b/manual/tunables.texi
index 713f669c4c..9052c56d9b 100644
--- a/manual/tunables.texi
+++ b/manual/tunables.texi
@@ -186,9 +186,9 @@ path, or the basename of such a path.  The process name is read from
 AT_SECURE is in effect).  Example:
 
 @example
--glibc.cpu.x86_shstk=1
+-glibc.cpu.x86_shstk=on
 [proc:/usr/bin/program_that_crashes_with_shstk]
-+glibc.cpu.x86_shstk=0
++glibc.cpu.x86_shstk=off
 @end example
 
 @end table
-- 
2.55.0