remove code slide from example

plugin/markdown/example.html

@@ -18,17 +18,6 @@
 
 			<div class="slides">
 
-                <section data-markdown>
-                    ```php
-                    public function foo()
-                    {
-                        $foo = array(
-                            'bar' => 'bar'
-                        )
-                    }
-                    ```
-                </section>
-
                 <!-- Use external markdown resource, separate slides by three newlines; vertical slides by two newlines -->
                 <section data-markdown="example.md" data-separator="^\n\n\n" data-separator-vertical="^\n\n"></section>