Documentation: kprobetrace: Fix code block markup

This display the following code extract as a code block instead of a
normal paragraph.

Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20230121225304.1711635-3-yoann.congal@smile.fr
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/trace/kprobetrace.rst

@@ -161,11 +161,11 @@ You can add and enable new kprobe events when booting up the kernel by
 "kprobe_event=" parameter. The parameter accepts a semicolon-delimited
 kprobe events, which format is similar to the kprobe_events.
 The difference is that the probe definition parameters are comma-delimited
-instead of space. For example, adding myprobe event on do_sys_open like below
+instead of space. For example, adding myprobe event on do_sys_open like below::
 
   p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack)
 
-should be below for kernel boot parameter (just replace spaces with comma)
+should be below for kernel boot parameter (just replace spaces with comma)::
 
   p:myprobe,do_sys_open,dfd=%ax,filename=%dx,flags=%cx,mode=+4($stack)