Prolog cookbook: Fix heading of example 9

Change-Id: Ie323a67f78718fe83ff836b7883479395fdf11f6
Signed-off-by: Edwin Kempin <ekempin@google.com>

Documentation/prolog-cookbook.txt

diff --git a/Documentation/prolog-cookbook.txt b/Documentation/prolog-cookbook.txt
index d31c401..22c2b21 100644
--- a/Documentation/prolog-cookbook.txt
+++ b/Documentation/prolog-cookbook.txt
@@ -741,7 +741,7 @@
 Which of these two behaviors is desired will always depend on how a particular
 Gerrit server is managed.
 
-==== Example 9: Remove the `Verified` category
+=== Example 9: Remove the `Verified` category
 A project has no build and test. It consists of only text files and needs only
 code review.  We want to remove the `Verified` category from this project so
 that `Code-Review+2` is the only criteria for a change to become submittable.