Correct heading level to 3

Arnd R. Strube · Arnd R. Strube · commit a68b469c372a · 2016-03-03T13:14:37.000Z
diff --git a/plugin_manual.markdown b/plugin_manual.markdown
@@ -137,7 +137,7 @@ IEEE754ExceptionsPlugin::enableInexact();
 IEEE754ExceptionsPlugin::disableInexact();
 {% endhighlight %}
 
-# Example
+### Example
 
 {% highlight c++ %}
 #include "CppUTest/CommandLineTestRunner.h"
