Fix formatting of example blocks

With the new stylesheet example blocks (delimited with ====) are
rendered as rather intrusive boxes with large padding in yellow
and grey.

This patch replaces the example blocks with simple code blocks
(delimited with ----) that better match the overall style of the
documentation.

Change-Id: Id95387cdb153332c2066e2d5e378697647dbca52
Signed-off-by: Michael Ochmann <michael.ochmann@sap.com>
diff --git a/Documentation/cmd-logging-set-level.txt b/Documentation/cmd-logging-set-level.txt
index fcf9311..5baa968 100644
--- a/Documentation/cmd-logging-set-level.txt
+++ b/Documentation/cmd-logging-set-level.txt
@@ -33,16 +33,16 @@
 == Examples
 
 Change the logging level of the loggers in the package com.google to DEBUG.
-=====
+----
     $ssh -p 29418 review.example.com gerrit logging set-level \
      debug com.google.
-=====
+----
 
 Reset the logging level of every logger to what they were at deployment time.
-=====
+----
     $ssh -p 29418 review.example.com gerrit logging set-level \
      reset
-=====
+----
 
 GERRIT
 ------