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-set-project.txt b/Documentation/cmd-set-project.txt
index a0f8cf2..11cb74c 100644
--- a/Documentation/cmd-set-project.txt
+++ b/Documentation/cmd-set-project.txt
@@ -103,10 +103,10 @@
 Change project `example` to be hidden, require change id, don't use content merge
 and use 'merge if necessary' as merge strategy:
 
-====
+----
     $ ssh -p 29418 review.example.com gerrit set-project example --submit-type MERGE_IF_NECESSARY\
     --change-id true --content-merge false --project-state HIDDEN
-====
+----
 
 GERRIT
 ------